thats just it, what a program does is artificially produce wind, if everything is right, and you set for your kestrel reading and miss, then you guessed wrong, so if you missed before you shot in a steady 10 mph wind, what happens is a variable one?
thats my thing, get everything I can control as close to being right as I can and better results will be obtained. but if your off 6" before you shoot whats the best you can expect?
the majority of my LR deer shots involve 16-30" of windage adjustment, when your waiting for the shot, take note of the amount the grass or limbs are blowing in relation to what they are doing at your position, with practice it comes around, had one bad hit from a wind call, missed POA by about 6", it was still a bang/flop from 600 yards.
RR