Okay so we booked a bounceback for this September while we were there in December. My question is are you allowed to add a day if the room is available and still get the bounceback price?
You should be able to. I booked the bounceback when I was there last Sept for the first week of this Sept. After I was home a few months I decided I'd rather go for the Food and Wine Festival, so called to see if I could change my dates and still keep my free dining. The CM had to go through guest services, but I was able to change my dates to Sept 26th-Oct 4th and still keep the free dining. They even asked me if I wanted the same number of days. They said that as long as I had the Bounceback ressie in the system that they could move it around.