Maybe Elliot's Prius is the wife's car.
I'm still wondering how my wife dropped my awesome FE from Milwaukee. It was at 54.5 mpg at 145 miles getting to the East side of Chicago. I fell asleep and she drove and at the hotel (a mere 30 miles later) it was 51.5 mpg at 175 miles!!! How can one possibly lose 3.0 mpg over 30 miles after the car has already gone 150 miles. Almost like she was driving in second gear at 5,000 rpm with the A/C on. I asked her but got the same blank stare that she was just driving like she normally does. I didn't let her drive the next 450 miles home but I was able to nurse it up to a 53.1 mpg readout at home (calculated as 56.8 mpg though).