When you remove the water bowl how quickly does the RH drop to the room. I use one hour as a max. (one air change per hour).

If that is ok for you that is great. I am glad you have a solution. Personally the thought that the thermometer and thermostat can be wrong by 4º in either direction and the IR gun are (almost always) spec'd at +/- 2ºF some are worse. (did you check you guns specs? You should) would make me very nervous.