Just a quick thought here, that's based on more than a few years of flight checking instrument procedures. Whenever a DME beacon is involved, I'm always checking to ensure that there are no embarrassing DME "unlocks" during a turn that shields the aircraft's DME antenna for more than the briefest amount of time.
Perhaps I've missed something in all of this but wouldn't it be an idea to ask the FAA why they want to flight check this procedure?