Well in the case of KPOP I understand they were making significant changes throughout previews so I have a harder time considering them as performances in this case. I know my Playbill on the Saturday before the originally scheduled opening wasn't reflective of the song order as it was presented at my performance. And from other things I've read significant script changes were being introduced on a regular basis. People who saw the show multiple times in previews shared how much it had improved from the beginning until opening. Had the show been frozen in week 1 and then not opened until week 5 I think that's a different scenario.
