CCPU top bow hole question

[wrndln]

I bought a top wood kit for my CCPU that was made by Classic Wood. I noticed that on one end of all four bows, one screw hole was drilled and countersunk perpendicular through the end of the wood. However the other end was drilled at an angle, maybe 25 or 20 degrees toward the end of the bow. Does anyone know why the holes are drilled differently? Also, why are they different and which end with the angled hole goes to the front or rear. I suspect the angled hole is probably to reduce the chance the wood below the bow doesn't split. If that is the reason, why aren't both ends drilled at an angle? I am posting pictures of the ends in question with a dowel in the holes to show the angle of the holes.
Rusty Nelson