Yes, I agree we know our bodies better! It's hard for FF to pinpoint it too when things don't always fall into 24 hr. increments. I know it was early am on cd17, so it's close enough to what it says, but we dtd am on cd 16, which would be about 24 hrs. before O then we dtd at noon on cd 17, which would be about 6 hours after O...so I would have liked it closer, but oh, well. Worrying won't change anything now...