I’m so confused about how the app calculates an average cycle length?

Mine has always said 28 days. I just went back and calculated 30 months of my cycle lengths and got the average of 26.667 and so on.

It’s almost 27 days. I don’t know how they are calculating that my average cycle is 28 days. Any advice?

I think I was TTC too late because I was going off of the app (I did use tests for a few months.)

Lately I’ve been paying more attention to my CM.

Am I doing it all wrong?

We tried a little earlier this month (our schedules are insane) so going off a 27 day cycle (average) which would put BD right at the perfect timing, versus early on the 28 day cycle. My CM was very much so egg white the two days we were able to BD.