Time Asleep Score

[BrianSC]

I have FB premium and I understand that the sleep score factors in many variables. 

That said, the "Time Asleep" portion of the score is puzzling. This portion of the score only takes into account the duration of your sleep. 

The other 2 scores for "Restoration" and "Deep & REM" provide scores for the quality of your sleep.

If my goal is 8 hours of sleep and I reach that goal (taking into consideration the type me awake), then my "Time Asleep" score should be 50.

If the 8 hours wasn't good quality, then that should be reflected in my "Restoration" and/or "Deep & REM".

If this is not the case I'd like to understand why it's called "Time Asleep" and not something else.

MODS: I've seen this question asked quite a few times, each time receiving more or less an off topic copy/paste about the holistic scoring system. I just want to know about the how "Time Asleep" is scored. Please stay on topic, thank you! 

[DeSMP]

Great question. My time asleep score rarely changes, whether I am meet my goal or exceed it, even by an hour, and even when my time awake is at the low end of the benchmark.