It's not as scary as it sounds, it doesn't flick between heavy regen and coast, I was just trying to say these are the two extremes. If say you're going along a straight level road, with nothing in front, and you lift off, the car will coast along. If you get to a steep hill, or a sharp bend and you lift off it will apply regen. It isn't perfect, but it does do a fairly good job of doing what you would have done in the same circumstances in an ICE car (except you'd be using the brakes to slow obviously).