Versa 4 is not tracking my sleep times accurately

[Phineform]

Let’s say I sleep from midnight until 8 am, but Fitbit incorrectly says I woke up at 6 am.  How is it possible that if I edit my sleep time to 8 am, that my sleep cycles change to include my cycles between 6 and 8?   If they know I was in light and then rem sleep from 6 to 8, why would it have first reported I woke up at 6?  This doesn’t make sense to me. 

Moderator Edit: Clarified subject

[Guy_]

@Phineform- in continuation of your other post, editing a wake time [the time the watch thought you woke, so it ended your sleep and made a sleep score]  will alter the calculation of the sleep for the longer or short periods and you can get a new score.

However it must always be monitoring possible sleep patterns at rest because it can record naps of less than 3 hours and so it has a partial record of the state you were during that time, it just won't calculate a score or provide the pattern detail unless it is at least 3 hours.

It is a good question and probably the watch starts monitoring during periods of complete inactivity, low heart rate.

Generally the sleep start and end times are pretty accurate.

The awake duration that causes a single sleep to break into 2 sleeps may not be known because it can also be based on activity as well.

There is a sleep sensitivity setting on the web dashboard, view device settings that may changes things slightly, I use sensitive.

[Phineform]

I understand what your saying, am set on sensitive and I do agree it’s generally close enough to accurite.  But using this example im still puzzled by this, which happens to me maybe once every 2 weeks.  It incorrectly reports I woke up at 6 am.  I change it to the correct time of 8 am.  It then says from 6 till 8 I was in light and then rem sleep.  If it knows I was in light and then rem sleep at the time, why would it report I was awake then?  It makes it seem to me that it’s just making up that information.  If it thought I was awake it clearly didn’t know I was in rem sleep. 

[Guy_]

@Phineform - probably best summarised as follows.

What the watch detects and what the app calculates and shows are distinct.

Such that short sleeps don't calculate/show stages or scores but when combined with a long sleep it can then do the calculations and show the details.