Sleep score goes down with more sleep

[Wkalkman]

Often when I wake up at five or 6 AM in the morning, I’ll check my sleep, score… And it may say 85 with 6 1/2 hours sleep for example. Then when I wake up again at seven or 7:30 AM, I check it again and it’s usually lower like 79 or 80? To me it should go up when you get more sleep? Can anybody explain this? 

[LZeeW]

Hello @Wkalkman and welcome to the Community.  The sleep score come from a proprietary (secret) algorithm that looks at both quantity and quality of your sleep.  Your sleep stages only account for 25% of your sleep score.  Premium users see additional sleep analytics.  In addition to your Sleep Stages, you get a Time Asleep (50% of the score) and Restoration (25% of the score).  The Time Asleep looks at how much time you slept compared to how much time you were in bed.  Restoration looks at how much time your sleeping heart rate was below your resting heart rate and how much time you were tossing and turning.