This miscalculates its own data. The "luteal phase" is the time from your day of ovulation to your next period; mine appear to always be 16 days long. I don't know where the "stats" is pulling its luteal phase numbers from, but they're off!
OH, I see what it's doing, it's calling the period from the beginning of your period to the beginning of OVULATION your luteal phase. FAIL!! The luteal phase is the time from ovulation to the START of your next period!