Aha, it is not a 7-day average, but an average over a period of (7 * 24 * 3600 = ) 604,800 seconds. If you were running seven days ago at the end of the day and today at the beginning of the day, then both activities fall within the period of 604,800 seconds. Then the number you display is indeed correct.
I am used to looking at kilometre totals at the end of the day. And the seven-day moving average is then the total of the past six days + today. That way, it doesn't matter when you ran on the day.
The way you do it now I find less useful.
Is it an option to add the calculation method I described for the 7-day average as well?
(Or maybe replace your method?)