....(snip)....edited to add that Carol already helped you while I was typing! So it is just random, Carol? I thought a certain % was owned by WDW?
My understanding is that the rooms owned by Disney are kept to handle administrative issues (maintenance, overbooking, etc.). If not needed for that purpose, they are often sent to CRO/WDWTC and offered to the general public for cash. Unlikely that these are released at the 11 month mark, but I suppose it could happen.
By far, the largest number of DVC rooms that are offered via CRO come from DVC members who elect to use their points for a non-DVC WDW resort or for a cruise on
DCL. DVC has to get cash to pay for the members who "trade out" and that is how they get it. No one really knows how they select the resort and dates for that purpose. From my observations, they seem to stay away form high demand times.
For lower DVC demand periods, DVC has sent rooms to CRO/WDWTC as early as 11 months prior, but that is relatively rare and October does not qualify as a lower demand period for DVC - at least not for the EPCOT DVC resorts.
DVC rooms offered to CRO also come from developer's inventory - these are rooms from the portion of the resort that has not yet been sold to DVC members. While this doesn't apply to BWV (or BCV or OKW or VWL), SSR and possible AKV still have rooms in this category. (I'm not sure about AKV - it is selling so quickly that I don't think they have any units ready for occupancy that haven't been declared into the condominium (i.e., belong to members).
Anyway, those who want 2 bedroom units for cash via WDWTC/CRO just need to call periodically after the 11 month mark passes. Another option is to explore renting a reservation directly from a DVC member.