So I've archery hunted for years and hunt pretty high in the air. My question is I've had people say you will shoot high when shooting down with a regular bow and I've never experienced this has anyone noticed this with a crossbow?

Did some tests. From 20' up to 30 yds out, w/in an inch.........

The issue I think folks are eluding to is that you need to aim for the horizontal distance from the base of the tree to the target, not the distance from where you are sitting to the target.

Practicing from an elevated position will give you a great feel for how this works out.

I have noticed that when shooting from high up in a tree, I generally hit a little higher on the target than when on the ground. It is much more pronounced at close range (10 yards or less) than at longer ranges. I forgot about it last year when taking a close shot on an 8 pointer. I was aiming for the heart on a quartering-to shot (I know, not recommended) and the arrow hit about 6 inches high in the base of the throat. Thankfully the arrow severed some major arteries and the deer fell within sight.

I agree that there is a tendency to hit high. And for me the higher I am up, the more often For me, it is the really close shots ... 5-10 yards or so from the base of the tree that are a challenge. It is easy for me to hit 3-4-5 inches high ... I have even hit across the back, on the oppposite side of the body. Not sure why, but I think it is foprm related. Bending adequately at the waist in order to hold form can be tricky. The tendency I have on very close shots is to not bend far enough, and I end up "reaching" out from the waist up, which is not good form for sure! On shots say from 15 yards out, I do OK, with most shots very well placed. I do struggle with 40-45 yard shots simply because of the lesser margin for error associated with longer shots. Always have. These days I usually pass on shots past 40.

I think its pretty much like this...when your sittin high in a tree your mind and your eyes adjust and set up thinking the shot is farther than it really is. You might choose the 30 yard pin when its really 20-25 yards or something and then you shoot high. Practice practice practice and you will be fine. Some people are good at judging distance others are not. Practice and a rangefinder and that should work. mistakes are part of learning. just don't miss the big buck! ha

Gravity acts on the arrow over the HORIZONTAL distance of it's flight. (From tree to target at ground level). Being higher or lower can affect the aiming point to ensure vitals are hit but it does NOT affect trajectory.

You also need to bend at the waist so you hold the same shooting position as you do when standing on the ground.

That's true with a vert, not an issue with a crossbow (what the asker postulated)