Sorry, forgot to get to this last night You can find the half point value of anything by looking up the push percentage. When you have a closing line in the 2.5-3.5 range, the 3 hits around 10% of the time. So you'd have.....
45 wins
45 losses
10 ties
By grabbing 3.5, all those ties turn into wins, so you'd go from 50% to 55%.
122/222 is 54.95% so the fair price for that 3.5 ticket is -122.
The fair price for the 3 was -100. This makes The half point off 3 worth 22 cents. It's worth slightly more getting on the 3 from 2.5. Value will also fluctuate with the total. The lower the total the more a half point if worth