Power Attack’s description says “You trade up to 5 of your attack bonus for that much extra damage on melee attacks.” The “up to” part is, in my experience, unique to DDO. Does it mean that Power Attack can only help and never hurt?
In other D&D-based games, as far as I know, Power Attack always gives the full 5 penalty to your attack bonus. For example, if—after considering everything else—you need to roll a 10 to hit something, and you roll a 13, with Power Attack, you’d miss, because 13-5 = 8 and 8 is less than 10. This “up to” phrasing makes it sound like instead of missing, in DDO you’d hit and do 3 extra damage. 13-5=8. 8+2=10, so you only used 2 of your "up to" 5 points, leaving 3 for damage. Is this how it works? I know DDO departed from the PnP system, but the question still applies, just with different math. This was just the simpler way of explaining the question.