I guess we saw the purpose of the +5 weapons comparison differently. I meant it as a reference point, not a hard ceiling, and felt it was useful to look at reasonable DPS growth potential since Shade labelled this a "MAX DPS" build.
My understanding was that offhand attacks suffered only with regard to STR damage, not to-hit. If that is correct, then PA would not affect offhand any more than main hand. Or is there another factor I am overlooking?Secondly, you have to-hit problems with your offhand if you do that with power attack on. It drastically reduces your to-hit in the off-hand (more than the difference between the OTWF feat that is a big part of the discussion), and you need a well-equipped character to overcome that. This set up actually makes power attack something you'd want to turn off if your target has 30 AC, and the plain pair of +5 dwarven axes (power attack off) take a significant lead at the end of the curve.