I think this is how you are supposed to bet the runline, say the team a was -150 and even at -1.5 vs team b, instead of betting 100 at -150, you bet 50 -150 and 50 -1.5 at even. If they lose, you lose 125, if they win by 1 you split, and if they win by 2 you win the original 100 you were going to bet at -150. Now risking 125 to win 100 instead of 150. It just minimizes your losses, GL!