Estimated Battery Life Remaining

On my 1050 when I toggle on battery saver mode the estimated battery run time remaining actually decreases. Software bug?! Additionally- how accurate is this time estimate as the % decrease I see per hour would give me a shorter run time than what the estimate says. 

  • any thoughts on this? Also, I have to significantly limit features to get close to 20hrs battery estimate which would be ~5% burn per hour (phone connection off, screen brightness at 30%, no navigation, only 1 sensor (HR) connected). Would be nice to know if this is in expected range or I have bad battery