IF all the nights are same resort, same villa size, same type, same view - IOW exactly the same room:
Just make sure that before the trip (I’d say at least a week or more) you contact BOTH Disney cash reservations and DVC MS, give both of them ALL the confirmation numbers, and ask them to put Continuing Stay notations on all of them. That lets the room assigners know you want to keep the same room. And when you arrive for the first reservation, go to the front desk and ask if you’re assigned to the same room all through. If not, that’s the best time to fix it.
DVC will want to keep you in the same room, to save housekeeping cost.