The last time these teams met was 10 days ago. Old Dominion won, 85-80, in overtime. Both teams shot well from the floor. But that final score shouldn't disguise the fact that Florida Atlantic is a strong defensive-minded team. So are the Monarchs. They also play at a slow pace. 
These teams are familiar with each other having just met. That's a plus for the defenses. 
This is a netural site setting, too - the Ford Center in Frisco, Texas. That's another plus for the Under especially given Old Dominion's track record there, which is five games played in the last two years all of which fell below 121 points.