If there is availability, I would think they would allow it since they will be making more money off of you. I know once I had a split stay, 5 days at PO-FQ & 5 at AS-S. After checking in, my DH decided he didn't want to go to AS-S's at all. I asked at the front desk & they switched my ressie over. I was allowed to stay at PO-FQ for the entire 10 days ( I did have to have the re-check in paperwork done on the day I would have been leaving & checking into the AS's but kept the same room)