Typically it is due to not knowing things such as injuries and such as timely as the NBA. The NBA has less than a tenth of the teams that are in D1. Injuries and other things are better covered in known. Books know if they post an erroneous total, that is where they will get hammered and end up with a lot of one sided action. So they wait to make sure they have what they feel is a good #. Totals also have a tendency to move more than sides. For instance last night's ND/Prov game opened at 155 before it was bet down to 150. You would be hard pressed to find such a line movement on a side.