The main reason people cross over the pushrods or pull-pull cables going to the tail is so that the pushrods exit the fuse at a steeper angle. If you don't do this, you have to either cut an extremely long slot in the fuse where the rod exits, or you have to put an offset bend in the pushrod, which weakens it. The slight increase away from perpendicular between the pushrod and control surface is insignificant.