This happens almost every time I switch moods if I'm not medicated! I use te same analogy too - the light is either on or off. Generally when I come out of hypomania or even the rare mania there is no warning - I go from an 8 to a 3 sometimes over the course of the day. My last depression it was like I breathed out - I sighed - and everything shut down. I hardly ever get periods of baseline in between if I'm not on meds. Last unmedicated baseline was actually exactly one year ago when I manged to be normal for the whole I my spring break before shooting up into the stars.