my 2 cents

1. HM contacted you as he promised, that's a very good sign. Otherwise, you'll come here and ask: "HM promised to call me by today, but hasn't, do I still have a chance?"
2. HM might've got some feedback from other interviewers in some areas, so he asked a few more questions just to make sure you are the right one. Very Normal. Another good sign that you are still in the game.
3. You don't have an offer yet, so relax and wait. Don't over think.

Good luck.