Magic Damage Order of Operations

[Mougurijin]

Yeah, something like "Successive Cast Bonus" sounds good.
However, this doesn't really apply to Impact any more than it does to like "Burn" or something, just Comet and -ja spells.

As for "SDT", it does seem likely to be part of the resist term.

When I was testing the resist term on the Ectozoon, as a BLM99 with dINT = 0, MACC = 0 and Elemental Magic Skill = 0...
On Windsday, for around 10+ casts each, Stone IV and Blizzard IV were pretty much always 1/8 resist, but Aero IV was never less than 1/2 resist and sometimes even no resist.
Then when it switched over to Iceday, for another 10+ casts each, Stone IV and Blizzard IV were still virtually always 1/8, and Aero IV was still always either 1/2 or no resist.

So would that effect come be SDT, as a kind of forced "unresist" for Aero IV ?
I also wonder if Hpemde's double damage taken effect would be SDT, as a 2/1 resist or something...

---
Oh yeah, I forgot about MTDR before.
It is applied after -ja "Successive Cast Bonus", and before Staff Bonus.

I haven't managed to test Comet with this too... it would be a little complicated as you need to cast Comet on two different mobs close together, and then cast an AoE dark element spell hitting both, all within 60 seconds...

So...
D > "-ja Successive Cast Bonus" > MTDR > Staff Bonus

"-ja Successive Cast Bonus" > MTDR

cINT=109 (113-4) [BLM99/rdm49]
tINT=105 (Ectozoon @ Abyssea Uleguerand)
dINT=4 (109-105)
M=2.299, V=782 (Waterja) [Firesday, no weather]
MTDR = 0.8 (2x 105 INT Ectozoon)
Water "-ja Successive Cast Bonus" = 1.05 (first cast = 15:40:14, second cast = 15:41:01)
MAB=1.5 (40+10)

A = MTDR > "-ja Successive Cast Bonus"
B = "-ja Successive Cast Bonus" > MTDR

	D	* 1st	* 2nd	* MAB
A -->	791	632.8	663.6	994.5
B -->	791	830.55	664	996

In-game damage = 996  (first cast = 948 damage)

MTDR > Staff Bonus

cINT=110 (113-3) [BLM99/rdm49]
tINT=105 (Ectozoon @ Abyssea Uleguerand)
dINT=5 (110-105)
M=2.299, V=782 (Waterja) [Firesday, no weather]
MTDR = 0.8 (2x 105 INT Ectozoon)
Staff Bonus = 1.15 (Neptune's Staff)
MAB=1.5 (40+10)

A = MTDR > Staff Bonus
B = Staff Bonus > MTDR

	D	* 1st	* 2nd	* MAB
A -->	793	634.4	729.1	1093.5
B -->	793	911.95	728.8	1092

In-game damage = 1093

[Yugl]

Request: Can you run that same test on Sahagin using water spells? Or maybe even crabs. If you get a resist beyond 1/16, that would show they are separate terms.

Answer: I never thought about SDT in terms of damage plus, but that's an interesting concept. If it works on the same term as resist, we would need to explicate that. At the moment, I cannot think of another mob with that property, but it is an interesting area to look into.

[Foldypaws]

So would that effect come be SDT, as a kind of forced "unresist" for Aero IV ?
I also wonder if Hpemde's double damage taken effect would be SDT, as a 2/1 resist or something...

I doubt it's a resist term. I would expect sure that's the same term as things that have "+ magic damage taken" (Or just +damage taken in the case of Hpemde's) like on the Rancor collar or Onyx gear.

[Mougurijin]

Request: Can you run that same test on Sahagin using water spells? Or maybe even crabs. If you get a resist beyond 1/16, that would show they are separate terms.

I'm already planning to test SDT on Sahagin, hopefully tonight.
To my knowledge though, I've never seen a 1/16 resist, at least not in the terms of the same spell cast on the same mob being able to do any of either: no resist, 1/2, 1/4, 1/8, and 1/16.

On the test server, here's how to get Elemental Magic Skill = 0...
In MH, set your job to something like WHM/WAR, and set level to 99 with the test moogle (this caps all the skills used by your main/sub jobs, and also resets unused skills to 0. WHM is good because you get enfeebling).
Next, without changing to the job you actually want to be yet (as your skills cap again when you leave your MH), use the test moogle to teleport to a place with nomad moogles, like Rabao.
Now change your job to BLM/RDM or whatever, and you'll have decent/capped Enfeebling, Enhancing, Healing, Weapon and Defensive skills; while your Elemental Magic Skill will be 0.

Using this for Elemental Magic Skill=0, along with dINT=0 and no MACC+ from gear, by far the most common resist I was getting with Stone IV and Blizzard IV on a mid-80 level worm was 1/8.
Surely in this situation, 1/16 resist should be pretty common, if not the most common resist? Yet I haven't seen a single one.

I also want to test on Clionid, as they resist certain elements too, but I haven't found out whether they have SDT, MDB, or TMDA yet.

I doubt it's a resist term. I would expect sure that's the same term as things that have "+ magic damage taken" (Or just +damage taken in the case of Hpemde's) like on the Rancor collar or Onyx gear.

That sounds like it could be true for Hpemde, so it will be interesting to see if it's part of the TMDA term as DT+100%.
For the Ectozoon commonly getting 1/2 instead of 1/8 resist for Aero IV, it can't be something like MDT+200% as this would allow Aero IV to do 2x or 4x damage for no resist.

[Mougurijin]

After playing around with some Sahagin, all I can see so far is that SDT is applied after Staff Bonus, but before MAB, and before Day & Weather.
It looks like it will be very hard to test if SDT is a separate term from Resist, as the only known SDT I can use is the -50% which Sahagin have.

With Elemental magic skill = 0, MACC = 0 and minus INT gear, I've been getting 1/8 resists with Water IV, which look like 1/16 resist because of the -50% SDT.
I haven't had anything worse than 1/8 resist with spells of other elements still.

I couldn't check whether SDT is definitely applied after Affinity as I don't have a Water (or Thunder) magian staff...
So the order I have at the moment is:
Staff Bonus > [SDT <> Resist] > Day & Weather

"Bubble Armor" seems to be MDT-50%, which I noticed only works if applied after MAB, so:
MAB > TMDA

I'll try and figure out if SDT is a separate from Resist, but it could be impossible to test without a different SDT value to use.

[Yugl]

Elementals have a 1/16 ish SDT I believe; it's easy to check before doing the test. Aerns resist light as well. Affinity is before SDT and the data can be found within the links on this BG Wiki page. If elementals are 1/16 SDT, then it's easy to see when you get a resist (Would be 1/128 on 1/8 Resist). If you use mobs that have less than 1/16 resistance, be sure to check other elements. BG-Wiki shows the max resistance at 1/8, but I could have sworn I've seen 1/16 somewhere else. If someone else can confirm one way or another, that will narrow this a bit more.

[Mougurijin]

Well I've already realised that it doesn't make any difference at all whether Resist and SDT are separate terms or in the same term.
As long as the only possible values for both terms are 1/2, 1/4, 1/8, and so on, and as long as one is applied immediately after the other, then it makes no difference to the result which way round you apply them, or if you just combine them in the same term and truncate once.

I guess it's still interesting if "SDT" can lower Resist to say 1/128, so I'll try your idea with the elementals when my internet is a bit more stable and I manage to get back ingame.

I should probably have read back through the whole Magic thread again to read what you and Radec already posted about SDT.
I couldn't find test information showing Affinity being applied before SDT though, although it does seem ridiculously unlikely that it could be the other way round.

[Mougurijin]

So far with testing, I've only been able to get 1/16 resists casting the same spell as the elementals, with 0 skill, 0 macc and negative INT gear.

It really looks like SDT is simply the forced part of the "Resist" term, which mobs/families can have to certain elements.

Standard "Resist" seems to be just: 1 (no resist), 1/2, 1/4, 1/8.

Resist probably has these values as it's caps: 1 (no resist) as the minimum, 1/16 as the maximum.

"SDT" probably force adjusts the no resist value, and can likely be: 1, 1/2, 1/4, 1/8, or 1/16, with standard resists of 1/2, 1/4, and 1/8 lowering further toward the maximum resistance cap.
If this is the case, then "SDT" can probably also be...
2 (possible resists = 1, 1/2, 1/4)
4 (possible resists = 1 or 1/2)
8 (no resists possible)

So 1/16 resist is probably impossible for the "Resist" term without "SDT".
Also, if "SDT" can be set to "4", then it would explain why I've only been able to get 1/2 and no resists for Aero IV on Ectozoons, whereas other elements are mostly always 1/8 resists.

[Yugl]

Unorganized post just spinning thoughts on this. Helps me think through the data.

If we follow Byrthnoth's model of resists, a clean explanation is that SDT adjusts the "Resist Level 0" term by changing the initial value and follows from there. However, this explanation would have difficulty capturing your 1/2 Aero test as it would quadruple the damage on normal nukes.

An alternative is to say that SDT forces you to start on a different resist level (Say level 1, for instance). However, we witnessed was that the value never dropped below 1/2.

The option of SDT being a separate term would help because we could say that (1/2) SDT combines with 1/8 resist to unlock 1/16 resist. This gives us a non-arbitrary means of explaining why 1/16 is only possible when the mob has an SDT. This also helps us explains why certain tiers of resist cannot be reached. However, it requires, as you say, that we cap "Resist" at 1 or 1/16.

In short, the main problem is that we need an explanation that forces reduced damage while forcing minimum damage. Moreover, the model has to explain why a new lesser tier of "resist" (1/16) unlocks and why the minimum tier of resist may increase (The 1/2 Aero test). Overall, I agree with your idea, but I was confused upon first reading it because we do not have the terms to explain what is going on. It seems that SDT and normal resistance function to form a single multiplier much like how MAB and MDB are functions of each other that form a single term. Thus, we have:

Resistance Damage Taken = The final multiplier [Upper Boundary: 1, Lesser Boundary: 1/16]
Resist Level = The normal 1-1/8 distribution
SDT = Species Damage Taken [If no SDT, set to 1; if 50% SDT, set to 1/2; and so forth]

Resist Damage Taken = (Resist Level)*(SDT) => Cap between [1,1/16]

When used in magic damage:
(Stuff)Affinity)Resist Damage Taken)Dy+Weather Effects)Other stuff)

[Mougurijin]

I found it difficult trying to explain what I meant in a clear way, I think you used some better terms.

I've been playing with Gully Clionid at Abyssea Tahrongi.
The ones at the camp to the east of Conflux #01 start out at lvl 74 and 75.

They seem to have MDT-25%, MDB II (1.12), and Ice & Water SDT-50%.
I'm pretty sure they have MAB IV (1.32) and the lvl 74 ones appear to have 90 INT, and lvl 75 have 91 INT.

They should make pretty interesting mobs to do testing on.

MDB has been confusing me... Otherwiki says:
"After calculating the ratio of MAB to MDB, this term is truncated to two decimal places"

When I truncate it to two decimal places I get incorrect answers, however, if I don't truncate at all after calculating the ratio, then I get much more correct answers.

[Yugl]

Radec found that during his tests too. The other-wiki was written before conducting our tests (And actually spurred the entire research). Also, Dy/Weather bonuses are strictly decimal values rather than 256-system values according to a test Radec asked me to do. I guess we should write that down on BG-Wiki once this is figured out.

[Mougurijin]

Seeing as this isn't really random magic "facts", more like ideas, I guess this belongs here instead?

This, I think, is the order of operations so far?

D > Cumulative magic bonus (Comet & -ja) > MTDR > Staff Bonus > Affinity > SDT - Resist > MB Bonus > MBB Gear > Day + Weather + Twilight Cape > MAB(+ M.Crit) / MDB > TMDA > (Stoneskin remaining HP) > DMG

I don't know if Stoneskin should really be included in the list, but it plays a part still.

Here are some other bits

Klimaform bonus > MAB
MAB > Goetia+2 set bonus
MAB > Ebullience
MAB > Phalanx
Phalanx > (Stoneskin)

Here is a list of other terms or factors not yet listed in the full order of operations, that I can think of...

Goetia+2 set bonus  -- 2~5 pieces of BLM AF3+2, bonus = +(MP conserved % x2)%
Klimaform bonus  -- Savant's Loafers +2 (SCH AF3+2 feet), +10% bonus, separate term from the Day & Weather term
Ebullience  -- SCH55 stratagem, black magic potency +20%
Phalanx  -- damage taken - x
Absorb damage taken  -- e.g. Shinryu. Also targets that can absorb certain elements
Hpemde double damage taken  -- occurs while a Hpemde's mouth is open

I'd assume Phalanx would have to be the last thing before Stoneskin takes part/all the rest of the damage, but maybe it's possible that somehow it isn't?
Also, as Stoneskin actually gets damaged by the spell, I'd assume Stoneskin must be the final thing, before the target looses HP to the amount of the final result DMG.

Although, if the target absorbs the spell and gains HP from it, wouldn't that be before Stoneskin? and would it also be before Phalanx or earlier still?

Also, are both "damage taken -%" and "magic damage taken -%" definitely calculated in the same term (TMDA), both using /256 system, and truncated just once?

I'm going to try to find the exact places for some of the remaining factors starting with Klimaform, Ebullience and Goetia+2 set.
I also want to look into MB as there are other sites that say MB Bonus is calculated before Resist.

I just thought I'd post all this in case some of this has already been tested, and if people might have answers to how and where in the order of operations the other stuff is calculated.

Edit:
Does anyone know of some mobs which can cast Phalanx?
It's annoying having to test by waiting for mobs to cast on me instead. They seem to realise which spell I'm waiting for and then they avoid casting it... :/

[Mougurijin]

OK, I found the "Absorb Damage" page on wiki, where HP gained through damage absorption ignores all damage mitigation effects like Damage Taken -%, Phalanx, Shell, etc.
Otherwiki goes further to list that it ignores Stoneskin, MDB and Resists.
I guess it didn't really belong in Magic Damage calculation at all anyway.

It should be pretty easy to find a targets INT/MND though if your spell is absorbed, if you really don't have to worry about ANY damage mitigation effects.

Playing around with Klimaform right now.
So far I've noticed it's definitely calculated before Day & Weather. So:

Klimaform > Day + Weather + Twilight Cape

I need to find out which side of SDT-Resist it is that MB Bonus is for definite, before I try to narrow Klimaform bonus down further.

Edit:
OK, MB Bonus is definitely after Resist. (and before Day & Weather, which someone also already tested earlier in this thread). So:

Resist > MB Bonus > Day + Weather + Twilight Cape

Now to test which side of MB Bonus and SDT-Resist it is that Klimaform bonus is calculated.

[Martel]

OK, I found the "Absorb Damage" page on wiki, where HP gained through damage absorption ignores all damage mitigation effects like Damage Taken -%, Phalanx, Shell, etc.
Otherwiki goes further to list that it ignores Stoneskin, MDB and Resists.
I guess it didn't really belong in Magic Damage calculation at all anyway.

It should be pretty easy to find a targets INT/MND though if your spell is absorbed, if you really don't have to worry about ANY damage mitigation effects.

There is one thing that I know of that affects absorbed dmg. A shield block will yield the blocked dmg when absorbed. But that only applies to physical dmg anyway.

Also... I've never tested if DMG taken + effects would increase the amount absorbed, but since PDT- doesn't reduce it, I'd assume not.

[Mougurijin]

OK, I gave up trying to proc Goetia +2 set bonus on Ul'hpemde while their mouth is open, but I'll try again later.
I found out some other interesting stuff though.

Ebullience is calculated after TMDA, but is calculated before whatever the Hpemde mouth open x2 damage taken bonus thing is. So:

MAB > TMDA > Ebullience > Hpemde > (DMG)

This was kind of annoying, as I was hoping Hpemde, Ebullience and Goetia all shared the same term, maybe called "Potency Bonus" or something, and just capped at x2...

Before thinking about Hpemde, I had previously assumed Goetia and Ebullience were probably the same term, as they both can't be used in the same spell cast by one person, as you'd need SCH55 and at least BLM83.
Now if I can find out where Goetia is calculated after MAB, in relation to TMDA and Hpemde, then it might be clear that it is a unique term.
All I know so far about Goetia is that it's after MAB.

[Yugl]

TMDA = ?

[Byrthnoth]

Total Magic Damage Adjustment?

[Mougurijin]

TMDA = ?

Pretty sure it's supposed to stand for Target Magic Damage Adjustment.

I'm trying to test Goetia +2 set bonus <> TMDA, but I haven't even seen the set bonus proc once, anywhere, since the update...
I haven't been using the complete 5/5 set, mostly 2/5 or 3/5...
But I originally found out about Goetia +2 definitely wearing just 2/5 pieces: Feet + Head (wearing Neck and Back too.)

I'm testing on Ornamental Weapons (the WAR Evil Weapons in Ve'Lugannon's Palace).
They have -32/256 MDT, and with my current set up, any proc of the set bonus will show which way round the terms are calculated...
However, with just Head and Body, I'm getting conserve MP procs but no set bonus ??? :/

Did they change something to require you to wear all 5/5 AF3+2 Goetia pieces to get the set bonus ?

Edit:
Bleh, I guess I'll just try to use the whole 5/5 set for now, I was trying to avoid M.Crit rate+5% from hands...

Edit:
Bah, the set bonus proc'd on the very first cast after changing to 5/5 pieces!!
...and it was the test cast on a new mob to determine dINT... and because I had dINT+91 instead of 92, so I couldn't use the result. :/
Well, it could just be a very big coincidence that wearing 5/5 pieces caused the proc that time...
It doesn't prove that 2/5 pieces can no longer proc the set bonus, but to be on the very first cast, after so many before it...
At least I now know the set bonus isn't broken completely on the test server.

[Mougurijin]

OK, from one more proc so far, looks like Goetia +2 set bonus is before TMDA !

Me:		BLM99/rdm49 -- cINT = 160 (101+59), MAB trait = +40, MAB gear = +26 (no Ice Potency merits)
Target:		Ornamental Weapon -- tINT = 68, MDT = -32/256, EXP = 45, Level = 74  (These are at Ve'lugannon's palace, lv74-76 -- As level 99: lv74 exp=45 tINT=68, lv75 exp=48 tINT=69, lv76 exp=50 tINT=70)
Spell:		Blizzard IV -- V = 506, M = 2, MP cost = 164
Day:		Firesday
Weather:	No weather.
BLM AF3+2 gear:	5/5 pieces + Neck + Back

MP before cast = 730
MP after cast = 597
MP used = 133 --> 13/16  (133/164)
MP conserved = 31 --> 3/16 (1 - 13/16)

Goetia +2 set bonus = 1.375  (1 + 3/16*2)
TMDA = 0.875 or 224/256  (1 - 32/256)
MAB = 1.66  (1 + 0.40 + 0.26)
Day & Weather = 0.9

dINT = 92 (cINT160 - tINT68)

D = 690  (92 * 2 + 506)

If:  D > Day > MAB > TMDA > Goetia
Then: 690 * 0.9 * 1.66 * 0.875 * 1.375 = 1238

If: D > Day > MAB > Goetia > TMDA
Then: 690 * 0.9 * 1.66 * 1.375 * 0.875 = 1239

My cast did 1239 damage.

I want to make sure a bit first though...

The proc was with full 5 piece set (the m.crit hands proc'd more often than I liked)...
I decided to keep using the same spell, Blizzard IV, even though it was Firesday, for which I received the -10% penalty on the cast...

Edit:
OK, I managed to get another proc on Earthsday with no weather.
This one is simpler:

Blizzard IV again.
The only gear change I made was adding an extra INT by putting a Buggard Strap +1 in an empty slot.
I did this because this mob was lv75 (48 exp) with 69 INT, whereas that previous mob was lv74 (45 exp) with 68 INT.
So the dINT is the same, dINT=92.
There's no possible day/weather penalty this time.
The MP change was from 1328 MP to 1205 MP, so Conserve MP proc = 12/16.
Goetia +2 set bonus = 1.5 (1+4/16*2)

1501 dmg = D > MAB > TMDA > Goetia
1502 dmg = D > MAB > Goetia > TMDA

My cast did 1502 damage.

So the order of operations for calculating magic damage, as I understand it, is:

D > Cumulative magic bonus (Comet & -ja) > MTDR > Staff Bonus > Affinity > SDT - Resist > MB Bonus > MB Bonus Gear > Klimaform Bonus > Day + Weather + Twilight Cape > MAB(+ M.Crit) / MDB > Goetia +2 Set Bonus > TMDA > Ebullience > Hpemde double damage taken > Phalanx > (Stoneskin remaining HP) > DMG

The terms in red (MB Bonus Gear, Phalanx and Stoneskin) may not be in 100% the correct place, as I haven't done any proper tests on them against some of their nearby terms.
I just wanted to include them to give an idea of roughly where I think they go.
Phalanx > Stoneskin is correct, in that Phalanx is calculated somewhere before Stoneskin.
I'm not really too sure about MB Bonus Gear at all though, as I've barely touched the stuff.

The rest of the terms I have tested against the terms directly before and after, so in my opinion they are pretty much set in stone.

[Mougurijin]

I was trying to test how Shinryu's ability Mighty Guard affects magic damage, but so far it seems it has no effect at all.
However, when I was posting some test data, I realised I got a weird result on one of my casts, and I can't figure out any reason why it happened.

The original post is here.

Here's the data from that post, with some additional data in blue -- all the spells Shinryu cast on me and "Quick Magic" procs from Atma of the Apocalypse.
This is the chat log from the video of a solo fight against Shinryu, using the moment events appear in the chat log and the timer on the video:

Me: WAR99/SCH49 + Brew, no MAB gear/atma
cINT = 999
MAB = 900 (10.0)

Target: Shinryu
tINT = 113
MDB = 70 (1.7)

Day = Lightningsday

Stone II capped D = 268 --> * (10.0/1.7) = 1576
Water II capped D = 321 --> * (10.0/1.7) = 1888
Aero II  capped D = 379 --> * (10.0/1.7) = 2229
Fire II  capped D = 443 --> * (10.0/1.7) = 2605
Blizz II capped D = 511 --> * (10.0/1.7) = 3005

Time	Spell		Dmg
---	---		---
2:06	Blizzard II	3005
2:15	Fire II		2605
2:25	Aero II		2229
2:32	Blizzard II	3005 HP
2:32	Thundaga IV (21 dmg)
2:36	Fire II		2605
2:46	Aero II		2229
2:54	Water II	1694  (Lightningsday)
3:00	Stone II	1576 HP
3:01	Stonega IV (16 dmg)
3:07	Blizzard II	3005  ("Quick Magic" proc.)
3:12	Fire II		2605
3:18	Aero II		1566  <-- No idea how yet, only just noticed this! ("Quick Magic" proc.)
3:25	Water II	1888
3:32	Blizzard II	3005
3:36	"Shinryu readies Mighty Guard"
3:37	Fire II		2605
3:42	"Shinryu uses Mighty Guard."
3:42	"Shinryu regains HP."
3:49	Aero II		2229
3:56	Blizzard II	3005 HP
3:59	Blizzaga IV (20 dmg)
4:12	Aero II		2229
4:20	Luminohelix	529
4:22	"Mougurijin uses Tomahawk."
4:32	Blizzard II	3005
4:43	Noctohelix	1064 HP
4:58	(Shinryu starts diving)
5:01	(Shinryu wings folded in, changed to defensive stance)
5:19	Blizzard II	2103
5:34	Aero II		1560
5:39	Fire II		1823
5:49	Blizzard II	2103
6:03	Luminohelix	370
6:16	Anemohelix	744
6:33	Hydrohelix	666  (Lightningsday)
6:46	Blizzard II	2103
7:06	Ionohelix	819  (Lightningsday)
7:27	(Shinryu does a twirl)
7:30	(Shinryu wings spread out again, changed back to default stance.)

After this brew wore off, for the second time, and I died.

For the other spell values and the full calculation order, see my talk page.
(Absorbed spells are affected by MAB and MDB, but NOT affected by SDT or Resist)

Can anyone explain the damage of the Aero II cast at 3:18 ?

The value and spell are definitely correct, and very little was happening at the time I cast it, also there were no gear changes the entire fight, etc.

My original theory was that Stonega IV somehow gives it's caster a +72 MDB bonus against Wind element magic damage.
I've tried to test this theory by repeating it, but each time my casts did normal damage after tier IV agas, so that theory isn't correct.

However, +72 MDB is still pretty much the only reasonable change that could decrease the normal damage of Aero II (2229) to 1566.

D > MAB/MDB > = dmg.

D = 379 (the cap D value of Aero II)
MAB = 10.0 (just brew)
MDB = 1.7

D * (MAB/MDB) = 2,229.4117647058823529411764705882

1566 / 2229 = 0.70255720053835800807537012113055

-- Not a new/existing term before MAB/MDB
No whole number before MAB/MDB works for 1566 dmg.
266 * (10/1.7) = 1,564.7058823529411764705882352941
267 * (10/1.7) = 1,570.5882352941176470588235294118
266.3 would work, but 266.2 is too low, 266.4 is too high, and it should be a whole number anyway.

-- Unlikely a new/existing term after MAB/MDB
These are the simplest values for a term after MAB/MDB...
Binary system: 2229 * (1 - 609/2048) = 1,566.4705882352941176470588235294
Decimal system: 2229 * 0.703 = 1,566.987
Stoneskin or Phalanx: 2229 - 663 = 1566

-- MAB (of caster) is unlikely to be reduced, and it wouldn't work out anyway...
MAB from brew = 900 (10.0)
MDB = 70 (1.7)
The simplest value that would work for MAB = 602.5 (7.025), a reduction of 297 and a half MAB...
379 * (7.025 / 1.7) = 1,566.1617647058823529411764705882

-- MDB is the only thing that could cause the damage to change from 2229 to 1566...
MAB from brew = 900 (10.0)
Shinryu's base MDB = 70 (1.7)
MDB needed for this cast = 70 + 72 = 142 (2.42)
379 * (10 / 2.42) = 1,566.1157024793388429752066115702

So... Does anyone have any better theories?
I don't want to have to stop using Atma of the Apocalypse when testing, and possibly no more Chainspell too... :/