I am certainly not “in the business” so I can only go off of what I hear in interviews and such, but my understanding is that they always film more than the 45 minutes or so that thy need for the episode and then the director and/or editor has options of what will go into the finished product. Sometimes a scene looks great on paper but doesn’t translate well on screen, or it doesn’t work with the episode as a whole. It certainly seems logical to have something extra rather than not having enough to fill the time. Somebody who knows television production methods could speak more intelligently to that than I.
As I recall the twitter message someone had asked specifically about any deleted scenes for
“Skin Deep” and RC replied that they had filmed a total of about 60 minutes, which would mean about 15 minutes of unused scenes. Don’t know if that was just Rumple/Belle scenes or just that this is their stndard practice.