If you look at a lot of treestand shot deer you will notice that due to the factors listed above most are hit higher than the archer intended.
Quite true. It is also true that you should hit higher when shooting from a treestand, than when shooting from level ground. When at a steep angle, you have to make sure the arrow takes out both lungs. It won't make much difference when the deer is out at least 20 yards and you're not high in the tree, but when the deer is in close or you are real high, the angle could cause the arrow to miss the far lung if you hit low on the chest.