If I say I'm cooking at 225*, I'm implying that where the meat is located in the cooker is at 225*. I may be reading temp from a variety of locations, but am taking into account that those locations differ from where the meat is by some factor, e.g. if I'm trying to cook at 225 on the top grate and reading thru the vent in the dome, I would adjust so my thermo reads, say 240.