Interesting thought.
Cedartown's elevation is 974 ft. Depending on this guy's home DZ, he could have about 500 feet of variance in elevation:
Mile-Hi - 5052 ft
Boulder - 5288 ft
Canon City - 5439 ft
So if we take the highest one of those, ~4450 AGL is the number I come up with as where the unit would think the ground would be. (or ~4075 if the jumper jumps at Mile-Hi). But that's ground level, not firing height.
Of course, as we all know, pilot chute hesitations & other things (density altitude, etc) could possibly affect an AAD fire, so it's all speculation until we see the actual data from Vigil.
I just thought I'd throw those numbers out there, in case anyone wanted to play with them a little more.
Wouldn't the pressure differences between the two environments (from weather) also affect the unit, not just the ground level differences.
I know we don't know if that's what happened just checking my knowledge.