I ran another test and you guys are correct. I installed TC #1 on bottom grate and #2 TC on upper rack. Set temp to 250 deg. 40 Min in #1 was staying steady at 250 and upper steady at 265. I expect temp difference of upper rack with the variables of heat rising and fans not running constantly when reaching set temp. Ran set temp too 300 deg and 30 min in #1 TC reading 304 and #2 325 deg. Another thing I am learning about this unit is how well insulated this pit is with walls not that thick from insulation. It does not resemble a Yeti cooler but if you need to drop set temp, opening the lid at least 30 seconds is a must. Looking forward to smokes this Winter.
Do the same test with the oven in your kitchen and let us know how it comes out. Would be curious to see. My guess is it will be less accurate, higher temp swings and temp ranges than your Memphis.
Z