SetPlanarEdgeRemoval Max 2012

I'm trying to subtract one object from another using the ProBoolean interface, however I can't get it to do it with while turning off edge removal. Is there anything obvious I'm doing wrong below?

a = Box lengthsegs:1 widthsegs:1 heightsegs:1 length:28.6071 width:26.6857 height:29.0322 mapcoords:on pos:[17.658,-4.15845,0] isSelected:on
 
b = Sphere radius:34.0183 smooth:on segs:32 chop:0 slice:off sliceFrom:0 sliceTo:0 mapcoords:on recenter:off pos:[24.944,-38.4505,0] isSelected:on	
 
ProBoolean ()
ProBoolean.setoperandA a
ProBoolean.SetPlanarEdgeRemoval a 0
ProBoolean.SetUpdateMode a 0
ProBoolean.GetPlanarEdgeRemoval a

The output from that last one is 1 not 0. I've tried every combination I can think of. I can get the basic subtraction to work but not the SetPlanarEdgeRemoval.

Thanks.