I noticed that too...also, I usually tape the probe to the bottom of the enclosure so I get a surface temp near the hide (or I place it right under the hide near the edge).
I found that Target has a better selection of Sterlites than Walmart....I know, I'm a traitor!! We had been trying to find a box that wasn't too deep but had more length, and we found what we were looking for there. Relatively inexpensive, about the same that Wally World charges.you wanna send me some of those boxes ! I have been looking for them for a while lol