From what I know of the setup and adding in my experience as a former EV owner (plus my Mom has a Fusion Energi (another PHEV)) is that during city driving and charging at home every night, you can achieve 70+ mpg. However, driving at higher speeds does not utilize the full benefits of the hybrid drive and you're most likely burning gas on your whole commute, due to freeway driving speeds. Same with the Prius, around town 50 mpg, take a road trip and stay at 70/75+ MPH and you only get 30 mpg since there is zero help from the electric motor. Plus getting up to freeway speed even using electric only mode, eats battery charge really fast. It's just a case of semantics when calculating the 'e' in MPGe