Ah, yep, you're correct. For some reason, I was sure two attacks from each off-hand was the maximum you can get pre-epic... That just makes my build even more ridiculous...

(Offtopic, Perfect MWF seems almost useless... since BAB doesn't increase past 20, you can't ever have more than 4 main attacks, right? So, it only gives you one more attack from each off-hand weapon, and at -15...
Oh, monks do get more than four main attacks, but they don't have off-hand at all, right?)