for most bowhunting distances, especially in a treestand, the math works out to be basically the same. However if you are out west on a ridge/cliff shooting at an animal that is down a 60 degree hill, and the range finder says 40 yards or so, it will make a difference.

It's more important to know how you personally hit when aiming up/down. Form matters and some people will hit high when aiming down hill.