Cliffcarter, by pushing the Therm. close to the bone you get a final finish temp. Due to all the juices melting around the bone, it cools off a bit , breaking down the Collegen and Muscle fibers (there's a long scientific reason,but...). When the bone releases , the meat is thouroughly done, going to a lesser temp. would tend to be more for Slicing the Butt. That would be at 165° or so close to the bone. Unless you have a boneless Butt, IMHO, I'd let it go to a little less and maybe it will pull not having the bone in.
Bone is cheaper for me and I like the flavor the bone gives...
Have fun and...