The brisket tasted like pot roast because it was in Foil to long. you should have vented it for 30-40 min before going in the chambro,the same with your butts, Don't blame it on on a higher pit temp. You had carry over cooking going on in the chambro. Probe tender at 240 and probe tender at 275 is the same probe tender.
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC