Wouldn't the best solution is just to go on the waitlist? Can you do that if MS is showing availability when you call? At least with the w/l it's an either/or proposition and no chance you'll have nothing at all. Just wondering....
I thought about that as well, but I think there might be two issues:
First, as you mentioned, I am not sure you can waitlist if they tell you something is currently available.
Second, I am not sure if the waitlist is real time, or only processes at the end of each day. If you were calling at the earliest possible minute of your 7 month window, had a confirmed reservation at your home resort, but were trying to switch to another resort, even if they would let you waitlist while they showed availability at that other resort, if the waitlist does not process in real time, others who call after you for that same check-in day at that other resort may get a room that you could have gotten if you had not waitlisted.
It is frustrating that members need to be so concerned with the specifics of the reservation system. However, if I had a confirmed reservation at my home resort for a busy night like say New Years Eve, I would hate to have any risk of losing it if I attempted to change to a different resort where I was told there was availability, only to find out I had lost both reservations before the transaction had been completed. In that case I probably would go the waitlist route, even if that might slightly lower my chances of the change going through. However, that does assume that you could waitlist when they are showing current availability.
One last thought regarding an earlier poster who was looking for two rooms. If you have two rooms at one resort and waitlist for two rooms at a different resort, is the system "smart" enough to only fill your waitlist request if you can get both rooms at the different resort, or does it fill them one at a time? If it did you might end up with rooms at two different resorts even by going the waitlist route.
As I said earlier, members should not have to be this concerned with the specifics of the reservation program, but if you are not guaranteed of getting your original reservation back if the new reservation cannot be completed, it is unfortunatly something that needs to be considered when making changes.