[Since this post was made, I've done further testing and posted the data. This can be found on page 3. Most of the data here has been updated as of 6/18.]
For the last couple of weeks I've been working on a project to map out Slow/Hojo/Slow II. My account was hacked earlier, and I won't be able to finish these tests. I'm going to post all the information I have because I think some of it is important, even though it is incomplete.
Slow 1 appears to follow a simple equation:
Slow % = (150 + dMNDx2)/1024
dMND = Caster's MND - Target's MND
This equation holds true for all dMND >= 0.
This equation caps at 300/1024, or dMND = 75. (~29.3% Slow Cap) This means after your MND is 75 higher than the mob's MND, extra MND only adds to accuracy and not to slow potency.
There is no apparant penalty for casting slow on a higher level monster.
Not once during my tests did a resist ever effect the potency of slow%. Resists only affect the duration of slow. A duration of 0 seconds results in a "resist."
Hojo: Ichi has a static slow% of 150/1024(~14.6%). This does not change /w any stat of your own or the target's. Casting Hojo: Ichi on bees outside gustaberg, easy preys, decent challanges, toughs, and ITs resulted in no change of slow% potency. As with Slow, potency was never changed and resists only affected duration. A full duration Hojo: Ichi is 5 minutes.
Hojo: Ni has a static slow% of 200/1024(~19.5%). As with Hojo: Ichi this does not change with any variables. The unresisted duration is 5 minutes.
Slow II appears to follow this equation:
y=Merits in Slow II
dMND = (Casters MND - Target's MND)
While dMND >= 0:
Slow II% = ([230] + [y * 10] + [floor(dMND * 1.6)])/1024
Slow II% cap @ (350+[y*10])/1024
dMND cap @ +75 MND
Slow II% is capped at:
1 Merit: 360/1024 (~35.1%)
2 Merits: 370/1024 (~36.1%)
3 Merits: 380/1024 (~37.1%)
4 Merits: 390/1024 (~38.09%)
5 Merits: 400/1024 (~39.06%)
When testing the cap /w Fraps and counting frames, there appears to be no change in potency /w 1 and 2 merits into Slow II. When testing Slow II /w 3 merits there was a clear change in cap. When testing Slow II /w 5 merits, there was again a clear change in cap.
Unfortunately there is some stuff I was unable to finish testing. I hope this information leads to more testing and a better understand of Slow II/Para II merits. Esp with the upcoming changes.