Hi.
Just adding pointers. Yes the choppers are pretty stupid, and i recall having troubles scripting chopper actions with altitude changes. If you script a chopper flying in over 100m altitude, then it might not follow the next waypoint commands or other stuff you'r trying to script with it. Donno why? I think the other air vehicles are usually more adjustable with altitude.
If you have too much speed when the unit's are making parachute jumps, it can cause unit killed or injured. Not allways but sometimes yes. 100m is usually quite enough for ok jumps. 0 speed/hovering jumps might cause units get stuck with another units chute below = unit injury or killed, sometimes but not allways
Recommending fast rappelling at low altitude/0 speed, there are scripts for doing that.
And if you make the units eject simultaneously = same problems might happen.
Sometimes it is possible that the unit looses the attachment to the chute in midair, and falls down = dead. Chute flows slowly to the ground without the unit. Donno why? I guess that it is OFP bug. I donno if anyone has made a "reserve Chute"-addon? That would be chool