There are several sources for those cash nights in October, none of which are transferable to points stays.
1) Points owned by Disney, or unsold points
DVC owns acquired through owner default, ROFR, etc. These points are not owned or controlled by members, and DVC can use them however they wish. Often they are used for promotions, like the DVC Ownership giveaways, or the Developers Points promotions for buying a contract.
For instance, a new resort, like BLT, may be 30% sold when the resort opens, so in theory, 30% of the rooms will be available on points, the rest are stil owned by Disney for cash reservations.
2) When a DVC owner trades out of the DVC system to the Disney Collection or Concierge Collection, those points are translated into a room reservation that is turned over to cash reservations to offset the cost of the trade.
Neither of these can be reclaimed for point reservations, either because they were never owned by members, or because a member
is technically booking a DVC resort stay, and then trading it for a non-DVC location.
A third source for cash nights is the 60 breakage inventory. Any DVC Points rooms not booked at 60 days is turned over to cash reservations. The income is used to offset dues. Look in the annual budgets for "breakage income." Breakage inventory can be reclaimed by DVC for point reservations, but I would guess that the actual amount of breakage inventory is extremely small compared to the other type of cash rooms.
There is also a 3rd inventory in addition to points and cash, and that is RCI inventory, when a member trades to RCI, a room is taken from points inventory and offered to RCI exchangers.
