Is it possible to improve on your overall board score in the AF? I recently found out that I was .7 points too low on my board score to be considered for a pilot slot. However, I scored high enough to qualify for an ABM position.  

Do you mean active duty or reserve/guard boards?

The process is pretty transparent, and a .PPT summary is posted in the UFT board page through the AF portal. It's a similar process to how OPR/promotion boards run.

So you could meet a different board, submit the same package, and potentially get better or worse scores, depending on who grades it. But, even better would be to improve your stats or work on weak areas. No magic bullet here.