Problem with damage calculation, Skill Damage is dealt twice

[Hajime_no_Owari]

When ever a character uses a skill it's damage is dealt twice.
For example: A character uses a skill on a monster
Damage shown from the skill is 200
However instead of taking 200 HP from monster's HP it takes 421(for example)
I figured that it's taking double damage, but when I go to Game_Battler3, to skill_effect and divide the final damage by two, this happens:
A character uses a skill on a monster
Damage shown from the skill is 200
However instead of taking 200 HP from monster's HP it takes 198 (it differs +/- from what it is supposed to take by a random small percentage)
Does anyone know how I could fix this issue or maybe where this problem might be?

EDIT
Problem solved

 

[Anonymous]

yeah listen to tibuda I'd just had that prob before and it was because of another script I had.

but tibuda's answer seems more likely. considering I haven't released any of my scripts yet.

 

[tibuda]

(it differs +/- from what it is supposed to take by a random small percentage)

you can change the variance in the database

 

[Hajime_no_Owari]

you don't understand, when I say differs from what it's supposed to take I mean the damage shown when fighting,
the damage amount pops up and it differs from what was taken from the enemy

EDIT
Never mind, the problem was at make_skill_action_result. I fixed it and it's fine now.