There is such a thing as "time lag". Since you have already re-set to 1 o'clock, leave it for at least 6 hours and see what is the reading. Give yourself the next 2-4 days to fine tune your setting. It should be between 1 and 12 o'clock. Also, the reading may fluctuate even when you don't open the door anywhere between 2-4 degrees for "open loop" cabinets.