Thats about right. I have tested my probes for calibration because I was concerned initially with what I was seeing with the guru and my 2 22" WSMs. I even thru a small oven thermometer on the meat rack to see what it read. Guru was correct. And as mentioned above clip the pit probe where the meat is but not touching the meat.
2X FEC 100, 2X 22" WSM, 1X 18" WSM, 26" Kettle, 22" Kettle, UDS