The door thermometer's quality is not the problem.
The heat runs right up that front wall and causes really high indicated temps.
So, you need to measure the temp further toward the middle of the cooker.
I spent many hours cooking and messing with mine.
I finally knew it to the point that I just dropped a probe thermometer in the vent and that is all I needed to know.
But, that takes time.
A probe in the interior is still the best way to quickly learn your cooker.
Makes Good Eats!
"Flirtin' with Disaster" BBQ Team (RETIRED)
FBA and KCBS Cook and Judge.
Former owner of a WSM, a Smokey Joe, a Charbroil Commercial gasser (junk), the legendary "StudeDera", a FEC100, a Fast Eddy PG500, and Sherman the Wonder Trailer.
Now cooking with a Yoder YS640
Proud Pellet guy cooking on real wood.