Seat1APlease
I can't see a 500 seater being able to give that punctuality, but time will tell.
As I understand all the preparations, the objective is to treat the a/c as (almost) two separate a/c. Load the upper and lower floors separately and do your uttermost to ensure that pax get into the correct departure gate and only staff and crew to traverse the stairs during loading.
Will carriers provide a double cleaning crew and then ensure the a/c is loaded by two doors on each floor simultaneously ...?? Whether this can be made to work, time will indeed tell.