JHanson,
MOBALL does not apply environmental conditions specific to your zero range when it's calculating sight corrections for long range shots.
As long as your zero range is 200 yards or less, that adjustment is not necessary. For example, if you establish a 200 yard zero at sea level, 32 degrees F (very dense air), a typical bullet will have about 9.14 inches of total drop at 200 yards. If you then go to 5000 feet elevation where the air temp is 80 degrees F (32% less dense air), the same bullet will have 8.92 inches of total drop at 200 yards. That means there is only .22 inches difference in drop at your 200 yard zero range in this extreme example. Bearing in mind that a single 1/4 MOA click is .52 inches at 200 yards, the drastic difference in atmospheric conditions will affect your zero by less than 1 click.
If you use a 100 yard zero, the effect is even smaller.
Now, if you set your scope zero for a long range, say 500 yards, then the feature you're talking about becomes important because a 500 yard zero can be significantly affected by differences in conditions.
I know that some programs have the feature you're talking about. I considered including it in MOBALL, but decided against it because the majority of hunters/shooters reference their drop from a 100 yard zero which is a policy I recommend for several reasons. If you use a 100 or 200 yard zero, then you don't have to worry about what the atmospheric conditions are when you zeroed the rifle, even if your program gives you the option to.
Hope this answers your question,
-Bryan
