I have a MES30, RdKnB has good suggestions. MES is famous for inconsistency in their temperature setting with the built in's. First thing I would do if you still have your Maverick, I would check for the possibility of a Delta T, or a difference between what its seeing and what its telling the unit. If you are unsure about the Maverick, use a ice bath or boiling water. Then having a guaranteed known use it to check the onboard setting. Once you know that, you'll got it make in the shade!
Oddly I have just tested my MES30 cooking a turkey high and dry. I have always used water before in my electrics especially for a long cook like turkey. Its not to add moisture, its to keep the turkeys skin from drying and cracking. What it actually ends up doing if to boil adding steam to the smoker.
