[Zeke]

Pretty obvious that the probe reading 30F in a bowl of liquid water is not working. And you will get different temps in the box if there is a lot of contents on the shelves. Empty should be a very close range when it's running or just after shut off. Don't put items on shelves in any way that they block the fan.

I like to turn mine down until the milk gets a tiny bit slushy in the coldest part (that would not be in the door racks where a lot of milk is stored), then go back a notch.