I got a new stove a few years back, everything was always undercooked and had too cook longer. Got a thermometer, here the temp preheated was 25 degrees lower all the time (i.e. set at 350, temp was 325). So got out my book, had to recalabrate it. Now if I set it for 350, it goes to 360. Grrrrrrrrrrrr. So I just set at 340 as the thermometer in the over says 350 (or 10 degrees lower for any wanted temp). I have decided technology isn't all that great, dumbing down syndrome. By the way, don't call customer service........just sayin'.