Yes- hidey holes are cooler than the outside part in Nature~ I suppose.
I have 6 cages heated by RHP's; mine are made by Rich at RBI and are the 80watt variety. On top of the warm hide it is the temp that I have my t'stat set to and under the hide (also made by Rich at RBI) it is two degrees warmer.
What type of hide do you have? RHP's warm the air as well and so the heat accumulates under the hide- mine at least!