I am making the assumption that the extra boxes are DVR's based on price... If you want to have a DVR in every room, you can buy an off the shelf DVR and just use the standard small cable box that is $2-3 a month instead. Why do you have such an expensive box in each room?
At least from comcast, its $3 for what I would call an HD repeater. You get basic functionality from it but you get all the channels you get on your main cable box. On the other hand comcast also offers a DVR for $15 a month. Why would you ever opt in to do that for each room?