From what I've read in the community recently, I was under the impression that the "stops implantation" effect of PlanB had come into serious question and that there's now a decent chance that it DOESN'T. As far as cervical mucous goes, I am unsure.

And yes, I agree that ovaries can be wacky, but most women most cycles will be non-fertile by 2 days from the end of their cycle.