I'm not sure but I don't think driving in neutral is a good idea. For example at least 1 generator is always connected to ICE (MG1??) and there is no way around it, so lets say you start going down hill and at 35 MPH switch to neutral, what happens when you speed goes above 42 MPH ? IS the ICE going to start up even in neutral or you're going to overspeed MG1 if ICE stays stationary??? And what happens to all that electricity generated in MG1 when battery is not being charged (according to manual battery is not charged in neutral even if ICE spins) suggesting the electrical connection to battery is not maintained. There is also a warning in a manual about towing TCH with front wheels rolling on the ground and towing would be very similar to driving the car in neutral down the hill. I would think driving in neutral on the flat road, where the speed would never increase would be fine, but now you're switching transmission back and forth, much more than maybe it was designed for and coming to that downhill where it almost begs to let the car roll in neutral brings that overspeed issue again.