When i start the day with high body battery level (>75) it always drains quite fast dropping to 60 in the first two hours or so, even with low stress levels. But when I start the day with battery around 50 only, it drains very slowly even with the same activities and stress levels during the day. In both cases and very comparable days I end up around 25-25 in the evening. How comes? Why this faster drain when Body Battery is high?