The old rule was whatever season, discount, etc was in effect when you checked in was what you were charged for the whole stay. So if you are checking in before or on Nov 19, then you can try for the VISA discount and you will receive the discount the entire trip, even though it goes over the holiday.
From reading the boards, it is my understanding that this perk will be gone starting Jan 2008, that each day is priced separately from now on.