Rashad lost his fights at 185 because he transitioned to that weight at the end of his career when he should have been retired. I grant you that some guys are better fighting up if they have a speed advantage versus their "right" weight, but overall, in my opinion the Jones fight showed that he was undersized. Interestingly you do see trends come and go in the various weight classes of guys fighting at their natural weight and then much larger guys will come in for a while and squeeze down into that class, then small guys arrive again.