TYPICALLY, a bow with belly mounted limb has a riser that shows less deflex in the riser. The deflex is at times, handled by the placement of the limbs on the belly. The limbs are already behind the pivot point of the grip.
But, a bow with belly mounted limbs can be made as straight as a bowyer wants it to be, or, even reflexed off the riser if a person were to decide to do that.
I don't know what the advantage, perceived or otherwise, would be in reversing the fadeout wedge in the limbs.