I have a 2012 Prius with 82,000 miles. I was normally getting 49-51 mpg, suddenly my mileage dropped to around 40-42 mpg. I've kept a close eye on it for the past several thousand miles to rule out differences in fuel fill-ups. The decrease seemed to coincide with the recall for a software fix. Could that have had anything to do with it? If so, how? If not, what might?