Well, if you are talking about deer ducking the arrow at the shot, I only aim a hair lower if the deer is alerted, but never off of the vitals. If talking shot angles, you want the arrow to hit higher than if the deer were level. Aim for the off side.
If you are talking about distance and such. Shoot the horizontal distance not the diagonal distance. A deer 30 yards out may register 34 yards on a rangefinder but the horizontal distance is only 30. If you hold for 34, you may hit high.
I support all hunters, regardless of weapon or technique!