Most Helpful Guy
NC purpose is for helping you move on. It's not for punishing someone passive aggressively so they would know not to take you for granted and want to hook up with you again.
You don't start and stop NC. You do NC consistently and constantly. A proper NC happens once and that's it.
Most Helpful Girl
If you completed the NC and he contacted you that is a great sign if you want to have your ex back. It is okay if he contacts you first (as long as the contact is positive and not negative). By contacting you it shows he is interested in you still and that is a good sign that you may be able to reconcile. I see no reason to need to repeat at all :)