Once you foil it, forget about getting a accurate internal temp for tenderness. U want to cook it about 2/3 the time u cooked it out of the foil if u keep the same temps. Shoulda took about 3-4 more hours in foil. Then rest in the foil for a hour or more. After the 3-4 hours I'd check for tender.
I go h n f. 325-375 3 hours then 1.5 hours in foil always tender. Throw the brisket on cold and I get a nice smoke ring.
