I've been checking almost those same exact dates for months (ours are 12/20-12/23) hoping for an AP discount (we've had a deluxe CL room booked since spring). We even called on the date the AP rates came out and there was nothing available for the room we wanted, and I think the regular CL rooms were either sold out already or not discounted. I just remember the CM on the phone saying that WL was super popular and that the dates always sell out very quickly. Still, it's worth it to keep checking! I'll continue to check pretty much every day until shortly before we leave.