I forgot to mention. I would put more stock in the TC than one of those oven thermometers. I'm only at 650' AMSL so water boils right near 212*. Also, a Styrofoam cup packed with crushed ice and topped off with water will drop to about 33-34* (if you work fast). If you can find a way to test the TC/PID combo with a known temp, it should set your mind at ease. I've only had to adjust one of mine by -2*. I could have left it since that's within tolerance but I was being anal at the time.
Ken