During active sales, DVD "declares" inventory for sales on an as-needed basis. Inventory not yet declared into "member" inventory may be used by the developer (DVD) for cash reservations and usually cannot be used for point reservations. This is the reason that there is still limited points availability at BLT since a lot of the resort is not open for members - but is available for cash reservations. With all of the other onsite resorts DVD still maintains about 2-4% of the rooms to allow for maintenance/rehabilitation shortages but the remaining villas are all accessible for point reservations - both for
DVC stays and for the non-DVC options where points are used by members (
DCL, other WDW/DL resorts, etc.)
The undeclared inventory can also be used at times by DVC Guides wanting to create "Disney Magic" for their new buyers.
DVD has always maintained declared inventory with some excess lead time for sales. They certainly don't want to have a situation where a sale would need to wait for the legal paperwork to be completed to declare additional inventory.