Are you setting a stop to stop the corner of the wheel on center or how are you obtaining the split point? Setting a stop is one method, but more uniform results will happen if you perform a third op on the flank to cut the back side of the flute to create an actual cutting surface at the center of the drill. I don't really know how to verbalize this. I will see if I can locate a pic to clarify.
Can you post a pic of your current results?