Exactly,But (as I have said before) there are areas of the rules that specifically state that a reservation being used as a rental must be communicated to DVC at the time the reservation is made. Not once you find a renter for it, not once you are ready to modify it, etc. Right when you make the reservation. If you do not follow that rule, they do not have to allow you to make the changes for a rental, even if they have in the past.
Just because DVC doesn’t bother enforcing the rule, doesn’t mean it doesn’t exist. Same goes for selling your transfers.