Fitbit Ionic vs Sleep study results

I just thought I would post images from Fitbit that I wore during sleep study so people can compare the results.

First link is page of sleep study and second link shows what Fitbit saw.

Fitbit said I got a lot more sleep then I actually did.

https://i.imgur.com/54ZxixN.jpg

Fitbit ionic https://imgur.com/a/7YYhB

I have a Fitbit Charge 2, and did a full sleep study a few months ago.

The correlation between the Fitbit data, in term of sleep stages guessed from movement and heart rate changes, and the PSG data, based on many electrodes, EEG, EKG etc., was very good and actually impressed the sleep doctor.