Well all math aside, I showed what someone flat betting would expect to "gain" over that period of time. But therin lies the dilemna of arguing these things. Not everyone flat bets, and that half point is most definately more valuable in certain situations than others, and certain teams are predetermined to be involved in more pushes.
So there really is no real way to put a real value on it. That is why math really can't be used. Because everyon'e numbers are going to be different.
If I look at another source I find that there have only been 585 games closing at -3, and the results there ATS are 274-260-49. So then you have to figure out where you stand at those results. Someone else might find another set of results.
So until we can all agree upon what the true results are, any value you place on buying on or off any number is theoretical.
For example, I will throw this one team out there as a specific. New Orleans Saints. Since 1985 they have been involved in 46 games where they were either a 3 point fave or a 3 point dog. They have been involved in two pushes over that time period. So had you bought off the 3 in their games you would be pissing money away as it would have only made you an extra winner twice. And what is so bad with a push anyways?
Obviously I picked the "best" team to show the discrepency. But to take it even further, one of the pushes involved Tenn, a team with high proencity to push. Since 1985 they have been involved in 53 games where the line was 3, they have pushed in 7 of them, that is roughly 13%, not the highest but still pretty high.
But when you take the teams like that that show higher than average push rates over a long period of time, and eliminate them from the overall results, it is pretty telling.
It is sort of like taking all the accidents in a given year between the hours of 12 AM and 3 AM, THEN eliminating the ones caused by drunk drivers, it is eliminating the highest probability factor. And it works, it is surely better than taking a league wide approach and then wieghting it the same way for every team. That simply cannot be done.