From which point do you range your targets?

There are two points of interest when ranging and calculating the trajectory and the needed compensation.

Drop/windage calculations are from the rifle’s MUZZLE.

Drop/windage compensation is from the scope’s GIMBAL.

Those two points can be far enough apart on an airgun to make a difference in certain situations. Certainly on very close shots (10yds to 15yds), but also possible on very far shots (>200yds) where a lot of correction is needed.