So, in hind sight the elevation number is a raw angle of the tube in mils with 6400 or 0 straight up regardless of the slope you are on. So, if you are aiming on a flat surface with an elevation of '1185' and hit, lets say a 300m target. If you move to a slope you theoretically should have the same angle because it's out of respect to your slope. Only limiting factor is if you can adjust your tube high enough to still hit '1185'. This is where it's wrong.

If you aim on a flat surface aka in the VR at a 300m target with an elevation of '1185' and move to a 15 degree slope and maintain a '1185' elevation this is an '1185' mils elevation in respect to the base-plate, not true level. So if you fire at an elevation of '1185' on a slope you now just threw your round a few hundred meters past your target. All you need to do is code it so the elevation indicator goes off a true level surface regardless of the slope you are on.