I got a combo rack from a local company that's a 6 shelf combo rack. Each shelf is either 2 15 quarts or 1 28 quart. It's a pvc rack with recessed 3" heat strip (belly heat). I have a herpstat 1 hooked up with the probe on the tape on the 3rd shelf from the bottom. It's under a tub, but I used some reflectix tape (small piece) to hold the cable right before the temp probe. I have my 4 snakes in 15 quart tubs on the top shelves (they're all less than 500g). I'm using a single layer of paper towels for now.

My question is, is it normal to have to set the herpstat to almost 100 and still not get 90 degree readings? I'm using an infrared gun to check temps and I'm checking the tub itself and not the paper towel. I am pulling the tub out about half way to check the temps and all along where the heat tape is has different readings ranging from 83 to 90 (a couple times out of the 20 or so times I've checked all the tubs there's been a 92 spot. Am I overthinking this? It doesn't help I'm still kind of new to bps so my two smaller snakes are usually climbing on a little ledge in the tub and when their tails fall off it makes a weird thump noise and one of my bigger females won't stop dumping her water (water always empty and paper towel always soaked, but bowl still upright). I've just seen a ton of videos on rack set ups and thermostats that are set to 92 for a 90 degree hotspot and I'm not sure if theirs is different due to higher ambient temps (my room is usually mid to upper 70s but the cool side of tubs is still 80) or that I'm doing something wrong.