Another technique to try is to stick a long tined (2 tines) fork into the point. If you can twist it 180 degrees without forcing it, pull it. If you can't cook it some more.
I foil at 165. You also might try doing the cook in an aluminum pan. *blutch ducks!* The last two briskets I did that way and they were incredibly tender.. I prefer more bark, so won't do that next time.