When mine have been out for a while and are noticeably colder they all wrap around my arm and then it looks like they try to move a little but can't. Well I've checked the temps of the snakes belly before and after doing that to me and there significantly warmer after so I always just assume there doing it to warm up.
Now when you say your monitoring the temps several times a day do you mean you look at the thermometer or take it with a temp gun Do you not have a thermometer in the viv ? I'd advise on getting one or two if not.