I personally didn't bother with that, I just zero Nikko sterling scope up for 30-40 yards, then learned to calculate the pellet drop at different ranges, using the small dots on the Mil Dot Reticle cross-hairs to compensate higher or lower depending on the range to hit the target, with practice you soon pick it up.
When I use to field target shoot, some shooters would use white tape, or paint the elevation dial white, & work out distant 50 yards or so, then you just dialed in the distance for each shot.
Shayper: Found this link, explains it better.
http://viriato.net/airgunning/bfta_setup_manual.pdf