Just to confuse the isue and make it harder for long range shooting.

If you shoot at a target inclined up hill or down hill, the bullet drop will only be for the horizontal range. However the effects of wind on the bullet will be for its entire flight distence as will its slowing due to air resistence.
So for a target 400 horizontal yds away at an elevation of 400yds gravety effects it for the equilivent of 400 yds but all other factors work for 565 yards which is the actual distence that the bullet travels.
So if you range an 400 yd uphill target at 565 yds and set a BDC scope for that range you will shoot high. It is not as far as the bullet is concerned 565 yds, however it is not 400 yds either :-(

I am not sure if that helps at all really

Regards