I just got my Oslo installed, and have had 4 fires now. It came with a Condar Chimguard, (Made in USA) Magnetic thermometer, and today I went out and got a Rutland, (Made in China), thermometer. With both of them in the front corners, they are tending to read about 100F different. I know they are close in accuracy, because if I put them in the same spot, they both read to less than 50 deg apart. In addition, the stove temp fluctuates from side to side. Is all this normal?