I wonder if some play calls 'RPO' meant run-pitch option - not pass. The film would reveal it. Linemen can't block more than 3 yards beyond LOS on passing plays- before the pass- or they get an ineligible receiver downfield flag. If the line fired off LOS at the snap, it might mean there was no intention to throw past scrimmage on that play.
This would enable the line to get more push and get 2nd level more effectively.
Just guessing. I'd like to look at the film.