According to S Wong's Sharp Sports Betting book based on 1990-2000 data a team given an extra 10 points covers 78.2% of the time and pushes 1.5% of the time. Similarly, if given 13 points a team covers 84.3% and pushes .9% of the time. Assuming that pushes = losses which, I believe, is the rule most places the 10 point teaser would win 47.8% of the time and the 13 point teaser would win 50.5% of the time. That means that you need to get paid +109 for the 3 teamer and -102 to break even on each. The above is a simplistic analysis that effectively assumes that all points are equal which is certainly not the case. One would have to see what point ranges the 10 or the 13 points add for an individual teaser.