This is a common question. The answer is that logistically the rooms
were booked by a
DVC member on points, then traded out to something that requires DVC to pay cash (any trade outside of DVC, except for Interval International). Those rooms are turned over to cash reservations to recoup the cost of the trade, and can not be recalled by DVC for booking again on points, as it would, in theory, be double booking the same room on points.