Thanks guys. This went on @ 5:00 PM, I set the Maverick up with an alarm for a keg temp of 300* for high & 200* for low, and a meat temp of 195*. I was concerned because I haven't been able to hold temps steady lately, been getting a rise after a few hours when doing ribs, even after replacing the gasket. This time went back to my standard Royal Oak for lump.
The temp settled in at 232* after a couple of hours and held steady until I went to bed at 10:30. Well, guess what? Maverick woke me up at 4:30 AM, thought crap. But it was the meat temp had reached 195*. The keg temp was 235*! I think someone had mentioned before that a Prime packer will cook faster than a select or choice grade. I checked it with my instant read and decided it could go a little longer so went back to bed. Set the Maverick for an alarm @ 200* and it woke me up at 6:30. Keg was still at 235*. I think I can conclude that lump does play a role in temperature stability. I haven't been able to hold temps that steady using Cowboy or B&B lump.