I dont know if this means anything, but as a biochemist, I've taken much organic chemistry and thermodynamics n my university days... and I have chosen to believe that Acetone does not increase mileage...
The article I read to convince me was this one
http://peswiki.com/index.php/Directo...Thermodynamics
Now the question is, will the acetone help clean the carbon residue in your engine to get back that 1 to 2% and still be perfectly safe to use?