My car was at the dealer's just this past week for an oil change, the hood seal recall, and the 40D update (which led them to blow the ECU and have to replace it)...I complained about the guess gauge and asked them to perform this TSB. They told me Toyota told them that (even though my VIN number was in the range for both TSB fixes) my Prius didn't need it and that they would instead recalibrate the gas gauge. After the way they handled the 40D, I was happy to have them stay away from my car for further work.
Rob