Lets look at the values of the first hits in the T2 training hall-
Acheron-
Damage min: 107
Damage max: 160
Combuster-
Damage min: 94
Damage max: 141
Amputator/CIV-
Damage min: 82
Damage max: 116
However, you see none of those numbers The damage formula in question is as follows:
base damage * multiplier - defense = damage dealt
Or for combuster/acheron:
total base damage * multiplier - (normal defense + special defense) = damage dealt
So how do you use this to buff the weapons correctly?