It's cooking faster than I thought it would. I put it on at 8:45 and it 10:55 now and internal temp is at 121.
You'll still have a challenge getting it done by dinner time. What you've got is what I did yesterday. 12 hours, but then I was trying to take it to 210 when normally I'd remove it a little earlier.
As it approaches 150 expect it to slow down and then stop for awhile around 160. If you're going to wrap it, do it then and worry less about even higher heat. Mine was wrapped in foil and cooking between 300-400 for a few hours to knock some sense into it.
Mine had a "second stall" around 180 because my pit cooled to about 220. It would have taken a ton more time to reach tenderness-done if I'd continued to nurse the pit along at 220-240.
So long as the first part of the cook happens at lower temps you'll be fine. Cooking at lower temps for the remainder is either a luxury, or better planning (earlier start).
I will concede that one downside to hitting it with higher heat at the end could be some dryer, "almost char" at the bottom of the pan. Sounds worse than reality! I'll gladly accept a little bit of that if it means I can eat same day.