Thanks for the replies, and yes I am only using temp as a guideline, and probing for tenderness.
I did a couple things and I think it's doing better. I am doing this in an electric smoker and I think it is too humid in there. After a few hours the meat looked wet, so no evaporation, so no stall. So I opened the door and let out all of the heat and humidity. It took a little bit to get back up to temp, and then what do you know, it stalled for a while. It has been climbing much more slowly since and is getting a decent looking bark.
Next question: when you all say "like butter", how much like butter? I started probing an hour ago, and it was not tender. Just a minute ago I tried and it feels much more tender to me, except in the dead middle. In the more tender parts a probe goes in easily and comes out easily but I wouldn't exactly say like butter. I'm giving it a while more in the smoker, just wondering exactly how tender you look for.
WSM 18.5, Smokin-It Model #1, Napoleon Prestige Gas Grill, MHP Grill, Purple Thermapen