Luteal phase

Ca
So sick of Glow assuming my luteal phase is 14 days. I enter my data of opk and cervical mucus and if it's after day 16 of a 28 day cycle which is normal for me it will predict my period to come later and it's always wrong. Then it does the same again next month.  We've been trying for nearly 3 years and we are going to head down the <a href="https://glowing.com/glow-fertility-program">ivf</a> path very soon but I don't know what to think anymore. I ovulate normally between day 16-18 of a fairly regular 28 day cycle....but GLOW can't seem to get this right. Does anyone else have this problem?