Upon further review, it may be a moot point. The Monroney sticker is meant as a way to help people comparison shop cars. So I looked at small cars and found this ranking:
The only cars with higher mileage are plug-in. The nearest ordinary car is 7 MPG worse, 39 MPG versus 46 MPG for the Prius c. This also means the 2017 Prius c owners are likely to see significantly better MPG than the Monroney sticker. But unlike the TDI, no cheating.
Bob Wilson