Yes, the story isn't like brain science here. Add a few more lithium batteries to a Prius and the mpg rating goes up. What is interesting is this is basically now a plug in hybrid that still uses gas. The original plug-in electric cars were generally derided because of their inflexible use. The big question is whether you could still take your plug-in Prius cross country without plugging in and still get your regular mileage. Commuting daily you get a definite advantage but you'd be held hostage. Oh one company has also turned a Chevy Suburban into a plugged in hybrid. Is this the future? Going back to the 1980s and plugging the car in?
New Lexus Flagship Hybrid Unveiled [internal]