My thoughts exactly..They look to have a better shape...more hook. I personally think that transfer shape has lots to do with performance.
Anytime a fluid is flowing through a vessel and you add volume (think cross sectional area) to the vessel, you decrease pressure. Velocity follows suit. You then need to increase the pressure to increase velocity. This tells me 2 things...the upper transfers time area will have a bigger impact on velocity with the larger covers. This may be why the 562 crank is stuffed.