I'll take a stab at this. I would say that it depends on the angle, and size of the target area you want your maximum point blank range to stay within. If we are talking about your bullet's trajectory staying 2-3" above or below the line of sight, then those ranges wouldn't be extreme and you wouldn't have to compensate much if any at all. For an elk not so much, for a squirrel... probably.
I have shot on what was called a high angle course a couple different places. However, neither was truely high or at an extreme angle at long distance. Seems for closer ranges (300 or so) we would just favor low and strike center mass. The problem we run into is with actually ranging with the reticle (we couldn't use a LRF). A hint to some of you guys that try this, you need an accurate target width as the height is deceiving looking up or down.
I would like to hear other's experiences as well.