I thinks it's easer to punch/ cut a sqaure rather then the half circle. this means cheeper remember pice to preformence ratio. And it just plane works. That's the big one.
I don't think they are punching these holes. I think they are all ran on a cnc. Plus if they were punching these the effort is still the same. All all that changes is the punch/die. <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> It is an interesting question.
