I've never relied on grill temps but can't believe how off the 2 are. Right now my thermometer says 234, while the built in one says 170. Makes me 2nd guess my store bought one.
Pork looks excellent although the process to get it there might have been a bit stressful. I own a MES 30 Gen 1 and, yes, I get temp swings all the time with it. My contention is that it all averages out to my chosen set point anyway. For tracking ambient temp and IT of the meat I use the Maverick ET-733 but it's a love/hate relationship. It's a great and accurate therm but they made it over complicated to program. So, programming's a hassle but after it's set up it's really easy to use. However, it doesn't have to be programmed to use it; you can just turn on both units, put the probes where you want them, and it will display the temps. You can track the smoke that way. Choosing a BBQ mode as to the type of meat and the target IT to be notified when it's been reached is a personal choice, just as it is with setting alarm notifications when the smoker temp hits either the lowest or highest preset temps.