Mine is stock and still likes to down-shift at points where I think (or would prefer) it coasts. t"m guessing they have programmed the trans to always down-shift where it can to prevent any lag when you hit the gas again. When I last had it in for service reported it as a concern as the trans was always trying to find a 'happy place' going downhill or even on the flat at 25-40 mph and they told me it was *normal* and that I had the latest trans programming installed.