Yep. Don't confuse "highway" for "best". My Prius v is rated at 44 city and 40 highway. If I drive it for extended periods on back roads (i.e. mostly around 55MPH) I can easily get 60+MPG. Optimal speed for any given car will vary depending on the engine, the gearing, and other such things, but typical highway speeds are usually beyond it. This is especially true with hybrids, which can reduce or eliminate a lot of the efficiency losses that normal cars suffer from at lower speeds.
That's remarkable. My Prius V (2013) gets about 49 mpg when I drive 55 MPH on smooth, level roads. A couple of times I've hit 50 mpg. Also, I frequent the Prius Chat forum and I've never heard of anyone getting 60+ mpg. Have you modified your vehicle? Is it a plug-in?
Weird. It's as stock as stock can be. I get 48-50MPG in my normal mix of city/interstate driving. That's on the clock, so de-rate by 5% or so for real MPG as calculated by miles on the odometer divided by gas purchased. Best I saw was 65MPG on the clock over a ~2 hour drive on various country roads coming back to my house, and not flat either (but a pretty minor net elevation change).
