Alan, Ron is right. That would throw the tiller off.
These are really neat bows as they are so versatile. By putting a shelf above and below, the shelf can be cut to center. Not the case when you put both shelves above the grip. This bow allows you to share it with a spouse, child or friend that needs less poundage and or shoots the opposite hand. It allows you to shoot less poundage for targets then hunting. It also allows a strictly right handed or left handed shooter to play around with shooting fingers but also play around with the thumb release.
I tiller these bows even and they can be shot three under or split. The idea of having two different nocking points for right and left handed shooting allows the shooter to tune nock height for both hands. Having the shelves both above the grip only allows for one nock point and that assumes that the shooter shoots identical with both hands.
The only down sides to this bow is there is no flexibility in grip style/shape. It has to be a low grip and symmetrical. There is a little more bulk in the tips which adds a small amount of extra mass which can rob a small amount of speed.