There is one thing you are forgetting about Jon.... When you use a shooting machine, you are cranking it back and hesitating for a moment prior to the release, rather than dropping the string with one smooth motion not allowing the limb to stop. It has something to do with momentum....
We've actually done tests with a shooting machine set ups that automatically triggered the release when it hits 28" with no stopping or hesitation the exact same way a flight shooter does. It has proven to yield higher numbers, than holding at full draw before release.
Granted.... In most cases your shooting machine numbers will be higher due to the release itself. but..... we are splitting hairs here.... Kirk