Based on the rule that you quote, there is no limit short of a full revolution.
Around here, we have a pitcher that usually has a straightforward windmill delivery. Every so often, she will exaggerate her backswing, bringing the hand up past the twelve o'clock position to where the ball is almost pointing at the batter, then come back around with a full windmill delivery. She ends up making about 1 3/4 revolutions with her arm from where she stops her backswing. As I mentioned, she doesn't do this on every pitch, just often enough to try to disrupt the batter's timing.
Our ASA UIC and his staff have all seen her pitch and have declared her legal.
It's usually pretty funny when she does this motion to watch the opposing team coaches start scrambling to find their (never been opened) rulebooks and justfy why this "has to be illegal"!
