To sell OTU points 11 months out they would need to have the specific points you needed on hand, for example BLT points to book BLT 11 months out, AKV points to book AKV 11 months out. Given where DVC gets these points it's doubtful that they have a proportional number of points available for all resorts so owners at smaller resorts like VWL would almost never get OTU points 11 months out and owners at AKV would almost always be able to get them. By restricting it to 7 months or less from check-in, they can sell members any points they happen to have lying around to book any resort. Every member has equal access to the pool of OTU points that way.