I think the final line on that game was +2. A more puzzling line to me was HOU/SAS. I had that game even according to my full season Vegas ratings, but HOU was favored by 4.5. The Spurs are 1-6 on the road now, so maybe Vegas is rapidly adjusting their spreads taking that into account.
Actually, I think that one has a simpler explanation: Popovich sat Duncan
. My rankings, like yours, predicted the line to be about even (0.5 points in favor of Houston). The final line ended up at 3.5 points in favor of Houston, which tells us that the market thinks Tim Duncan is worth about 3 net points over the course of a game. Using my offense and defense rankings (derived from the over/unders), we can even get more specific: My rankings predicted an over/under of 197 for that game. The actual over/under was 193. Using a little algebra, that means that the market value of Tim Duncan is +3.5 points on offense and -0.5 points on defense. Given that the rankings have an average error of 1.5 points, I wouldn't read too much into that -0.5 point. Basically, the market thinks Tim is worth 3 points, and those three points are due to his offense, rather than defense.
I did a similar analysis
on Carmelo Anthony last week (he also appears to be worth about 3 points, according to the market).