This took me a long time to get used to as well, but the MEATER should show a different ambient temp than Smoke because of it's proximity to a large hunk of cold meat. I've found that as the cook goes on, maybe after about 2 hours, the temp difference between the MEATER and the Smoke is almost completely nil.
If you look at the MEATER website they also address this "issue" and explain why it happens.
https://meater.com/support/ Look under the FAQ and the question that is worded something like :
"The ambient temperature reading of the MEATER is wrong!"
It explains the thermodynamics involved with the probe being so close to a cold piece of meat and the effects that has on temperature in that area.