no inaccuracy is not linear, it rises exponentially. an inch group at 50 will more likely get you 3" at 100. a 1/2" group at 50 will probably get you 1.5" in still conditions however i learned that in this kind of shooting you usually dial in for a condition, then depending on the highest and lowest variables of the wind you either hold abit left or abit right. that's how i usually manage to get some shots really close to each other. waiting for the exact condition doesn't work as often as one immagines.

if a 3mph wind drifts the pellet 6 inches at 100 and a 5mph drifts it 9inches, then dial for a 4mph wind which might be about 7.5MOA then hold 1MOA left or 1MOA right for windage. that is why it is important to have the reticle and turrets in same UNITS as i always hammer about.
It has to come to a point eventually where without having to work out many computations, you say "its a 3MOA wind" rather than goin through the whole process of working the correction for wind drift. people who have been doing this shooting for many years can tell you right away by looking through their spotting scope, how many MOA of correction you need.