My car seems just plain moody to me. Sometimes it gets "assist happy" and will show assist even when the instant mileage guage is around 55mpg with barely any throttle. Other times (especially when cold) the car does not like to use assist and will not assist even when the instant mpg gauge is down around 30mpg. I hate when it gets assist happy and prefer the way it acts when it is cold, only using assist when you really need it.