I tend to think of it as 3= boost, 2 = high and 1=low. Like a lot of decisions with the UI, they seemed to be designed to avoid battery drain. Similarly, high beam assist defaulting to off makes sense if you understand that they are trying hard to preserve battery life. The wipers were eventually changed, so that the sensor works all the time,and rightly so as it is more of a safety issue. All these things are a bit frustrating coming from an ICE car, but I appreciate the effort to preserve battery life.