If you want to change rooms simply because you don't like it (view, location, smoking pref), DVC rules allow for a charge for room cleaning ($25 studio, $30 1 bedroom, $40 2 bedroom, $60 GV). If there is something wrong with the room mechanically, they will not charge.
Have not had much luck in past (OKW) with preference request due mostly I believe to late arrival. Comming from Spokane.
I wonder if people have been successful with room change....if they pay the penalty...and go to the check in early next day.
If you're arrriving late, why don't you stay off site for the first night, then get up early and check in the next morning? Quite a few DVCers do it that way instead of using their points for that first night.