I made a bad mistake, well a couple of bad ones. I started early and cooked all day, well over 13 hours for these pork butts. So I was pretty tired by the end of the day. I had three butts on the top wrack of my UDS. The fourth was on the diffuser rack. I should have known that putting that pork butt on the diffuser was just like putting it on a burner even though it was in a foil pan. Second mistake was that I only probed the one butt on the diffuser rack. So when the internal temp of the bottom butt reached 201, I took them all off the cooker, wrapped and put them in a cooler. I then went to take a nap for a few hours. When I got up I discovered the butts were tough and hard to pull apart. The butt that was on the lower rack was way overcooked... DUH!!!
So I am gonna cook 4 new ones. THIS TIME... I am gonna only cook 2 or 3 at a time on the top rack only and I'm gonna monitor temps on all of them. This was a bad mistake but I'm glad it was pork butt and not a more expensive meat.