You are absolutely correct and the reasons you have given add up to there being no performance standard to compare or for any container to have to meet. Hence your AAD may just be decoration as 750ft is just some number!!.
Of course we could say that the time for a pilot chute to clear the container can be measured. The extraction force required to lift the free bag out can be measured. If they can be measured a standard can be agreed. With these known factors a properly packed reserve can be expected to fully deploy in X seconds. from that you can work out what height you would need to be at if traveling at a given speed for the reserve to save you. PHeeew. Problem is no one is asking the questions (except me) and when an incident occurs it is to easy to just say the AAD didn't save them, even if it worked exactly as it was intended to.
Anyway if someone sells you something intended to do a job why shouldn't they be able to tell you the limits of its operating capability. eg minimum safe height to initiate reserve deployment. They do give the Maximum speed and weight on the reserve canopy after all..
Just to be clear this problem can apply to any small free-fly friendly container especially with four or more flaps covering the top of the reserve pilot chute.
Start Asking your container manufacturer ????
(This post was edited by p.w.stockwell on Dec 6, 2012, 7:11 AM)