I'm sure it is hit or miss -- but in my experience...it is way more hit than miss.
As an aside -- I actually learned of this technique from one of the DVC concierges at VGF. I was in the midst of doing a checkin/checkout and she straight up told me that she recommends it to families and that she has had several regulars do single night bookings with doing the dining plan every other night. It is certainly no secret. She also told me that if you request up front -- it's almost never going to happen where you have to move rooms.