The problem there is sort of threefold. 1.) Amir doesn't play close enough to 40 minutes for that stat to mean anything, while McDyess does. 2.) McDyess is getting his numbers against starting centers and power forwards, while plenty of Amirs boards have been wrangled against the opposing squads dregs during the waning moments of an already decided game. 3.) Flip actually sees these two go head to head in practice. For all we know McDyess is the more successful of the two when it comes to their head to head matchups in practice.