Here is something to think about.Chances are the 20 is slightly high at 10 yards.Most setups will be 1" to 2"
OK,when shooting a deer at 10 yards from an elevated tree stand this creates a pretty good angle,RIGHT? Where do you want to hit when you have a good angle? HIGH,right? This ensures the exit will be in the kill zone as well.
SO,I say don't worry about it,aim for the center of the lungs,little lower if the deer is alert and let er fly.