Those numbers seem really optimistic. The best I've seen on a downhill section for about 30 + miles was a display of 37 MPG. If I am really conservative, I can average 26 with boosting. If I drive it how it wants to be driven, it quickly dips, getting around 22 mpg.
I boost cause I bought the car to, and that's my mileage. But I am also usually in backroads/single lane 55 MPH driving, so factor that in.