I elucidated in another comment.

e: Rereading that comment, maybe the connection didn't make much sense. In older cars, 10/2 was a better starting place for doing hand over hand, because if you wanted to turn (say) left, you'd start by pulling your left hand down and right hand left. Then remove your left hand, pull down with the right while grabbing over with your left. Switch hands, left pulls down, switch, right pulls down.

Starting with hands at 9/3 means you would have less on that first down pull with the left, and have to push up with the right. When every normal turn required hand over hand steering, 10/2 was more sensible.