The oddsmaker is giving too much credence to the Missouri Valley Conference being a defensive league with this low of a total on this matchup. 
Southern Illinois has surrendered at least 68 points in nine straight games. The Salukis rank 277th in defensive field goal percentage. They rank 10th in the MVC in points per possession and are last in the conference in 3-point defensive percentage. 
Missouri State averages 74.3 points. The Bears are fourth in the conference in points per possession and have the top free throw percentage in the league at 76.5 percent. They also rate second in the conference in two-point range.