Does really ellaOne delay ovulation?

To understand, we must answer a very simple question.

We all know that the pre-ovulatory day is the most fertile day of the cycle: the one in which most intercourse do occur, leading to most fertilizations.  If a woman has unprotected intercourse in that day, with ovulation within the next 24 hours, fertilization will follow within 24 further hours, that is within 48 hours since intercourse. EllaOne can be taken – with a consistent efficacy higher than 80% – up to five days since that intercourse, that is up to four days since ovulation and up to three days since the eventual fertilization.

How can any anti-ovulatory effect be claimed ?

In spite of this evidence, the EMA (European Medicines Agency), the AIFA and the most representative world Scientific Societies keep telling us that ellaOne prevents ovulation.