What a second, let's discuss pork shoulders. A full shoulder is a butt & a picnic in its entirety. If you have a butt you have the top portion of the shoulder, the lower portion is the picnic. Sounds like you have a Butt and a Picnic, not a butt and a shoulder. It may have been referred to as a shoulder roast.
The two pieces don't smoke the same, the picnic or shoulder roast can dry out quickly! The Butt, not so much. You have to do bad bad things to screw up a butt! (I'm speaking from experience here, hehehe) - I don't do picnics anymore, I'm not fond of the texture.
You can PULL well at 190, 195, or you can just give it a stink eye ;) at 205 and it'll fall apart on its on! Careful though, if you foil at the stall temp/mark and leave it foiled until you reach a pull or "stink eye" temp (known as the Texas Crutch) you may end up with the dreaded mush texture and a very Crocker Pot temp flavor.
If you are bound and determined not to wait out the stall and decide to foil consider foiling at an IT temp of 165-ish (stall temp) and UNFOILING at 192-ish (surpassing the stall in record time) to finish up to the 200-ish mark - put in a COVERED pan (not wrapping your precious butt, making it sweat all over its beautiful bark) for a half hour in a neutral/room temp area to let it settle! Poof! AWESOMENESS! No finishing sauce needed!