I suspect that reduced rate deal for an extra night over the holidays might be influenced by so much bad weather in many parts of the country. People cancel and now there are rooms to fill. Also can be helpful if someone is on site and flights home get messed up with the weather, so stay an extra night. High holiday room rates would keep people from booking, a reduced rate can at least get Disney some extra dollars for what would be an empty room, better to get something than nothing at all.