Mechanics are developed for the best possible, non-interfering method on the routine plays. However, the positions offered in the manual are merely starting positions. As the play developes, the umpire must move into the proper position which, as noted, does afford the best possible angle still keeping the ball, base and runner in front of you.

Personally, I believe the little ball mechanic of using 3rd base line extended is one of the worse possible positions, starting or otherwise, for a play at the plate in softball.

I've always thought that was a stupid mechanic!