No adjustment for altitude in the Army. Of course it works in reverse as well. My best 2MI run time was like 13.20 as I was always a 14 flat kind of guy and my second mile was faster than my first. On the flight back from Bolivia after living @ 15000' for 7 months we were offered a PT test the next day at Ft Riley. I was never a 300 kind of troop but I got close that day as I remember.