Hopefully @kezo will respond this evening. He may have a different take to me. When driving in HEV mode mine is showing around 20 mpg instant consumption, because the engine is using fuel both to propel the (heavy) car and to recharge the battery. Even if each mile in charging mode gives you an extra ‘free’ mile in EV mode, that’s still only around 40mpg which IMHO isn’t terribly good for a hybrid car. My 2.0i petrol BMW averaged 42.2mpg over 3 years and I would have expected a self charging hybrid to achieve more like 50mpg. I’m getting around 50mpg equivalent overall, but that’s only because I do a lot of miles in EV mode. The fuel computer shows way more than 50mpg, but that’s an incorrect figure as it takes no account of charging costs, so I work it out properly to get an ICE mpg equivalent.