Ok again you are focusing on timing the distributer.
I am ONLY talking about timing the cam to the crank. And that is irrelevant to distributer timing.
If the op times the cam to the crank at 10 and 10 you are saying the cam will be timed correctly.
I will take your word for that.
I find it easier to align two dots when they are facing each other.
I get that you are saying that then if you rotate the crank once after 10 and 5 timing you are then on tdc of the compression stroke for the #1 cylinder.