I am not sure I understand the question. If you have both a weeks and an RCI points resort you only have to pay the rci fee for the points account and it will also cover any weeks in a separate RCI weeks account.
In general you can book any weeks inventory with your rci points account. A lot of time I don't see the same inventory in both, I think it is just an rci glitch because if I call or chat and ask if I can book that with my points account if it is still available the answer is yes and they tell me how many points it would cost. I see 80%+ of the weeks inventory with my points account but not all. It sometimes seems to take a week or more of sitting in open inventory before it is visible through my rci points account and if I wasn't also looking through the weeks account I would never know that inventory was there.