I think even modern Olympic recurves etc (spits on floor) are set up slightly off from centre. Probably just to balance the string deflection as it slips off the fingers to avoid it kicking too muck right.
E.G If you shoot conventionally but put the arrow on the right of the bow it will just kick right off.
Mind, you can always cut to centre and then pad it out with leather, but like the others have said, wood is stronger than air...
I very rarely cut away an arrow shelf, in fact I've only got it on one flight bow and that is only cut away a bit.
Del