Fitbit reports vs Sleep as Android = Different results

Detailed description of the problem:

Of course I’m not expecting to have the completely same outcome, as the involved sensors are different, but when using my fitbit with SaA connected I’m getting some different analysis (especially on Deep sleep - Sonno profondo in the screenshots).

Wondering if I can help sending some debug data (from the wearable)

See:

Horizontal:

Or today:

Steps to reproduce:

Sleep :slight_smile:

Version of Sleep as Android:

20201010

Translations
Sonno profondo = Deep sleep
Sonno leggero = Light sleep
Risveglio | Sveglio = Awake

Different algorithms = different results.

Do you know which sleep result is right and which is wrong? I am not sure you can check it without professional polysomnography.