There is a huge misconception that the Las Vegas line is what the casinos think the score will be. This is not the case. The casinos are trying to maximize income but minimize risk. They want equal amounts bet on each side, they get their cut in either case. The line moves as more people bet on one side or another. The betting pros try to use this for their advantage. For example, the pros never bet on Dallas. A lot of money usually gets bet for Dallas regardless of the quality of the team, so the smart money usually bets against them; not because they don't like Dallas, but because the large volume bet for them moves the line in the other direction.