So as I have been collecting data to retool my betting model from last year I have been looking at line movements. In the 2009-2010 season, when the line dropped, favorites were more likely to cover the final line than the original line. In the case the line dropping 1.5 points like we are talking about here, the favorites covered the original line 42% of the time, but covered the final line 48% of the time. However when the line increased, the favorites became less likely to cover the final line.
Not to say you should draw any hard and fast conclusions from this because it is just one year's data.