Crazy, I'd think the fluctuations would be way too big. How long does it normally run for when it does a cooling cycle? Is that temperature throughout the fridge or only on certain shelves?

Ours (well, our landlord's) runs very consistently for 40 +/- 3 minutes, with just over 1h30min in between during normal use, or 1h54min if it was closed the whole time (like at night). The temperature of products, as measured with a cheap infrared thermometer that's probably off like 10%, varies between 2 and 7 degrees, but it's not very consistent between shelves (top seems warmer but then the very bottom one, that is only half deep, is as warm as the top again). The products I checked have all been in there for days; reflectivity may be part of the difference, not sure. I don't know what the air temperature difference is at the beginning and end of a cooling cycle though