The Offense table is interesting…It looks like the actual calcuation is something like: the percentage is (Offense – 1) * 7.7. That would mean the actual damage is:

Damage * (1 + ((Offense – 1) * .077))

Or, to put it another way:

Damage * ((Offense * .077) + .923)

I may be off by .1 somewhere, though, and I don’t know about the rounding. Still, I think it’s more likely that it’s this rather than a “percentage”. Log in to see images!