I don't think it's all that unusual for good availablity in January and September, even at the last minute. There is a reason points are so low then, and they haven't really done anything to push up attendance then like they have done for some other times that used to be slow. Early December used to be dead, but they have added all kinds of holiday activities that have made that a very popular time. Oct/early Nov used to be really slow, but they added the F&W Fest, extended dates for Halloween parties, & added some golf events, which have increased attendance at those times. Other than the Marathon (which is just a couple of days) they haven't done much I can think of to boost attendance in January or September. Those remain your best bets for booking at the last minute.
However, I was very surprised when I called a couple of weeks ago to change my late Feb plans from a 2br at BCV to a 2br at BWV, and it was available. I had expected to deal with a waitlist dilemma, and got the whole 5 nights immediately. It must be the week between the traditional school vacations and good old spring break. Lucky for me!
