I found the reason for my flocculation time was too long. When doing cheeses, I did dilute the rennet with water too early, meaning I deluted the rennet at the beginning of the making. So, the mix could easily be more than 1 hour old. And I have learned, that doing so, the rennet would be without any effect.
I did mix the water and rennet just before the mix had to be added, and then my flocculation time was 12 minutes.
Learning by doing.