Charge 6 Average Heartrate for Logged Excercises

[funnyusername]

I have noticed a discrepancy regarding my average heart rate for logged exercises on my Charge 6.

As soon as I finish the exercise and click the "Done" button I get a screen with some stats including average and max heart rate, distance, time, etc. 

I have noticed that the heart rate stats, both average and max, are different if I go into the app and click on the exercise I just completed. In particular the average heart rate seems to be 4-7 BPM lower that what was on the watch screen as soon as I completed the exercise. 

I also noticed that if I log into my account from a browser on a computer, I see the original data from the watch screen, NOT what is still being displayed in the logged exercise screen through the app. I can pull up the same logged exercise on my phone and on the browser and have different stats displayed for the same exercise.

What causes this, and which set of information is more accurate?

[funnyusername]

I forgot to mention (and can't figure out how to edit my original post) that this also applies to my Average Pace for an exercise like Run or Walk (with GPS turned on). The app will list a certain time, but the screen displayed on the watch immediately after I complete the exercise and the screen shown on a web browser both display a different (and usually slightly quicker) time.