I don't really have the time to explain right now, but I *think* the formula is:
Quote:
((Current HP/8)+AP)*%
an example would be:
lvl 5 238%
ap: 800
hp: 8000
Damage=((8000/8)+800)*2.38=4284

Ok, here's how I got it:
First I used it on torrobies a few times to get some data, the first part is my stats throughout the whole thing and the second part is the damage caused by each attack .
Quote:
Stats:
No equips:
AP: 931
HP: 8030
AP equips:
AP: 1165
HP: 8030
HP equips:
AP: 931
HP: 9141
AP+HP equips:
AP: 1165
HP: 9141
lvl 4 ap 211%
No equips: 4082
AP equips: 4576
HP equips: 4375
AP+HP equips: 4869
lvl 5 ap 238%
No equips: 4604
AP equips: 5161
HP equips: 4935
AP+HP equips: 5492

Then I made it look like this:
Quote:
lvl 4 211%

Normal AP: 931
Normal HP: 8030
Damage: 4082

AP: +234
Damage: +494

HP: +1111
Damage: +293

AP: +234
HP: +1111
Damage: +787
__________________________
lvl 5 238%

Normal AP: 931
Normal HP: 8030
Damage: 4604

AP: +234
Damage: +557

HP: +1111
Damage: +331

AP: +234
HP: +1111
Damage: +888

The first thing is that the damage cause by combining increased AP and HP is the same as both of them seperately, so we don't have to worry about that now. The second thing is that in pretty much all of the formulae involving ap, it usually adds on the ap before everything gets multiplied, to show that it also applies here, we'll isolate the ap section:
Quote:
lvl 4 211%

AP: +234
Damage: +494
If you multiply 234 by 2.11, you'll end up with 494, rounded up.
__________________________
lvl 5 238%

AP: +234
Damage: +557
If you multiply 234 by 2.38, you'll end up with 557, rounded up.

So right now we have:
As we don't know how hp is affected.
So now we add this section in:
Quote:
Theoretical lvl 0 100%

Normal AP: 931
Normal HP: 8030
Damage: 1935

AP: +234
Damage: +234

HP: +1111
Damage: +?

We get our theoretical damage by unmultiplying previous damage by the multiplier, then remultipling by 10.
We know that increasing ap will just be added on and multiplier, so we assume ap becomes 0 to get rid of it.
Quote:
Theoretical lvl 0 100%

Normal HP: 8030
Damage: 1004

HP: +1111
Damage: +?

Now you can obviously see that HP is divided by 8, if you want further proof, 8030/8=1003.75 which is close enough.
The reason why I said 'I *think*' right at the start is that i haven't tested it further using this formula.