Yesterday I got my ET-732 digital thermometer. Did the boil test two times and came up with the same results. Food probe 212° and the barbecue probe 214°. Today I checked my MES40's temp control and accuracy with it, to see how close the temperature readings in the MES40 are compared to the ET-732. I took some readings at set points 150, 225 and 275°. At the 150° set point on average the 732 read 5° higher, at the 225° set point 25° higher and at the 275° set point it was 23° higher on average. Temperature swing from set point was fairly tight. The MES' meat probe seems to be off 5-10° also but I still want to do a boil test on it. This was all done with the MES empty and the damper wide open. The 732's food probe, the MES' meat probe hanging in the middle of the smoker and the 732's barbecue probe clipped to the bottom of the top rack. Last Sunday I smoked 3 slabs of spare ribs and 2 butts with a combined weight of the butts at 17lbs. Used the 3-2-1 method for the ribs with a 235° set point. When I took them out they were nowhere near to being done. Finished them in my oven at 250°. Finished the butts in the oven also by choice. The first time I used the smoker I thought that it ran low in temp because I put a cheap oven thermo in the smoker that I thought was fairly accurate. I ended up smoking those ribs with a 250-255° set point in order to get my oven thermo to read 225. The ribs came out awesome. So now I'm a little confused with these temps and results. The only thing I can think of is that the butts, because of their size, weight and temp, pulled some of the heat away from the ribs? Anyway now that I have a good digital thermometer I'll have a better understanding of what's going on inside the smoker as far as temps go. I just don't want to get anyone sick and/or waste time and money. Any thoughts?