This is interesting. When I first got my car the first 300 miles my car would report "shift denied" fairly easily. I thought that the acceleration was a little slugish. Somewhere after 300 miles it was like everything just "turned on". When I downshift the computer blips the throttle like I would with a manual and it will downshifts at higher RPM's than before. The performance all around just got better. I thought that there was something in the computer detuning it during a breakin cyle but it might have just been the computer reading a lower octane gas from the dealer's first tank.
2010 Yellow 2SS/RS, L99 Auto, Grey Leather, Polished 20's