I got the update done on my 2010 a few weeks ago. Probably have about 300 miles on it now and getting better gas mileage than ever. I used to have a long term average of 38.6 or less in the last few months, but now it's over 39. On a 125 mile round trip, I got 41.9 each way, so it seems something worked differently for me than for some others. I had done the battery reset a few years ago and just left it when I took it to the dealer. They had the car for about 2 1/2 hours.