NCAA BASKETBALL MODEL

Hey guys, new to Covers here but I've created an Excel model for ACC basketball. (I know its late in the season but im a bored college student) It's not very original but basically it takes two teams median offense/defense ppg against the league median offense/defense ppg in order to create a basic prediction of the total points scored. In order to get a basic spread prediction I used the median home/away points per game. With back testing (only in conference games) its hitting about 55%. Now of course in placing my actual bets ive factored in other things such as injuries/motivation etc.