Apple Fitness App calculates weekly and monthly step count averages incorrectly.

Apple Fitness App calculates weekly and monthly step count averages incorrectly several days of the week or month. For example, my daily step count is 13000 plus each day of the month, yet on the 15th, the average monthly step count shows 10,388. Weekly averages are okay for a few days each week and then go haywire. It seems that the app is using more days than the actual weekday value to do the math (for example, on day 6 of the week, the app seems to sum the total steps correctly but then divides by 7 instead of 6 to calculate the average.) In the monthly calc, it seems to divide by a few more days that the actual day.