Sisters chart this month

MomofSoontobe4 • DH 7/31/12 💍 DS 3/28/13 DD 10/2/14 DD 1/21/19

My twin is TTC her 1st baby. She wears the AVA bracelet that’s why her temps are low because AVA gives low temp readings. I am posting her FF chart. Want to make sure her ovulation day is correct & looks like it occurred on the 10th. She had sex 3 days before the 10th & on the 10th & she is afraid she missed her window since she had sex on the day of ovulation instead of 1-2 days before. Anyone have insight? Anyone conceive on the day of ovulation? Thanks ladies ❤️