I know PCOS can cause ++ OPK's at many different times throughout a cycle, not sure about endo??

If you did O in CD 16 or 17 pg won't be showing up on even the most sensitive test yet. But pg hormones (very similar to LH and can be detected by OPK's) are most concentrated at night with concentrated urine. LH that causes the egg to be released is produced throughout the day so unusually FMU won't pick it up as well as arvo pee.

Hmmm... I would investigate endo as a cause of multiple ++ OPKs