My only experience with them is from the one I have ITC-306A, but I know it at least has that error. I have no idea which other ones do though. Apparently there are several differences between the models because someone else said they set a temp and then a variance of 1 degree so that it stays within a degree above or below. On mine I set the specific temp that I want it to turn on and then the temp that I want it to go off, I just have to make sure there is at least a .5 degrees difference.
Are any of yours wifi, I'm wondering if that is the difference?