Afflatus Solace and Magic Defense Bonus tests

[Vyvian]

So, I was going to try and get some data to see if I can figure out some ballpark values for how Solace affects MDB against that element, but I'm having trouble with the formula that it says to use in order to calculate magic damage.

BLM75/sch casting Thunder IV.
HQ Thunder Staff, 5/5 Lightning potency Merits
Casting with 334 skill and MAB IV(32) +11 MAB in gear.
77+29 INT.
Because we were dealing with barspells, I told him to cast in gear that would generate the least amount of resists, and on top of that, he used Elemental Seal on every cast.

I was the target (WHM75/blm)
No shell, base MDB on WHM, MDB IV (wiki says +16?)
INT 64+9.
MND 69+33

To start, I used no buffs, to get a base value. The result with ES was 708 damage, we tried multiple times and it was always exactly 708 damage. The problem begins here, if I plug this information into the equation, I don't get 708 damage. I get something in the high 800s-900s. I can get 700 damage if I assume I have 40 MDB, but I don't think that is the right amount of MDB for base whm.

I have 5/5 Barspell Merits, as well as Blessed Briault, so on the recast, we added +15 MDB to my base, theoretically 31.

The result for this was 648 damage.

Adding Afflatus Solace, with no HP cured (adding an unknown amount of MDB), made the result 630.
Curing myself with Solace up for about 1000 total HP (seeing if HP stored makes a difference), made the result 581 twice in a row with ES.

Can someone who is more familiar with working magic damage out maybe tell me where I went wrong, its probably something simple I overlooked on that initial damage.

106-73=33
33 x t4 modifier (2.0) = 66
T4 base for thunder, 541 + 66 = 607 base
HQ staff, 1.15x = 698
MAB/MDB (1.43/1.16) 1.23~x = 858
Nuke on a neutral day
Im not sure how the Lightning potency 5/5 merits factor in, but the number is already too large to get 708.
No shell, no damage reduction gear.
ES ensures accuracy on top of HQ staff and 334 skill.

[Kirschy]

pvp uses different magic damage formulas. Your best bet is finding a high level worm and having it cast stuff on you~

[Rena]

Solace gives +5 MDB.