They would also have to get those modifications tested by whoever certified the motor. But you are correct. I don't believe NAR has ever been approached regarding adjustable delays. TRA TMT pushed back on CTI to limit delays to a few finite steps, thus their clever adjusting tool. CAR allowed CTI to do infinite adjustment as Jerry advocates.
It's a combination of two factors: the level of liability the manufacturer is willing to accept, and the level the certifying body is willing to accept.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!