Well I stuffed seven 43mm x 18" ring casings and started them last night at 8:30 pm . Now we are a little over 13 hours into the smoking process. At the 11th hour the IT was at 150 and now it has dropped to 148 ! The smoker is running at a steady 170 . This is a 12.5 pound batch of pennsylvania deer bologna . Why does the temp go up and down like that ?