I've had the opposite occur 4 times in a row now... saying I drove too few miles. Of course all three were instances where I only needed a car because I was 1.) in a small town at night with no hotel shuttles or Uber/unsure taxi, or 2.) had a one-way from somewhere like Barnstable to BOS and they were trying to get rid of an electric vehicle they didn't want... all cases they told me to take either an electric vehicle or one requiring premium gas with saying I didn't need to put any gas in it. And I got charged for a refuel charge each time. Avis has the same story each time - known bug that if you are under certain mileage it automatically bills it.