If it was the release rate, then frequency would have made a difference, but it hasn't seemed to. And we also see a weird number of girls with people who have sex daily starting before the fertile window opens and going through ovulation (no one use this for a sway tactic though, it's too unreliable!!! LMK if you need more info, I have a long post on this) so I am not convinced it is a "sperm once a month" thing either.
