Casper is a full 1/2 second slower going from 2800' to 10,000' DA on the same 60'.
1000' DA? Heck that's GOOD air. We usually have to go out-of-state to find that. Even on a cold day, most our tracks are 2000+.
The only caveat is nitrous. Very little if any drop with altitude. Turbo's lose about 1/2 what a NA vehicle does, but it certainly drops.