Warning "smokin'" post ahead (that means LONG post for you new readers), just some random thoughts since it looked like you were needing more information.
Maybe it's symantics. A Plateau vs. a Stall.
Did you like it, were you happy with it at the temp you pulled it? How many butts have you cooked? I've cooked a lot and they can all have their differences.
The Butt plateau is in the 160's. It's based on food science and how the various parts of the meat are reacting to the chemical changes going on caused by heat.
I think you're Type A is showing
![Wink](/static/images/graemlins/icon_wink.gif)
That's not bad being a type A, but it just needs to be recognized in BBQ. Low and slow isn't just applicable to our BBQ, but to us as we're cookin' I know because more than once in life I've been a type A.
I've never seen a plateau that high. But that doesn't mean that the butt isn't just sitting on a temp -- basically stalling. The temp of the smoker has a lot to do with how fast it climbs. As it gets closer to the temp setting of the smoker it will stall on a temp.
Don't over process or over think it. Butts are simple. Put it in and let it cook. It's done when it hits whatever your target temp is. If you play the Type A game, then you start trying to analyze all the details of each temp and there are too many variable to discuss in a forum post.
I can't guarantee success for anyone if you're trying to cook this like a cake. In competitions, I'll have briskets finish anywhere from 185 to 205. BIG variation. Same with butts. I'll have some pull perfect at 185 and others need 205. I can pull two butts both at the same temp and one will be dry the other perfect.
That's why it's an art, not a science AND
It's done when it's doneHope that helps.
Smokin'