I'm not getting this issue. 2 weeks ago I did all my books in 9 days, so 1 book per day. The maximum it took to complete the fates was 4 hours on my first day, because I helped someone with a Trial inbetweeen and saw the fate end when coming back. Overall I've made the following observations:
- Fates from books generally spawn once per hour, ca 50% of the time around the full hour or half past.
- Fates in one book tend to spawn very close together, almost 5 minutes from each other. So it can happen that when you do the fate you need in one region, another needed has spawned 5 minutes before in another region OR will spawn any moment, so you better hurry.
Overall I have managed to get all 3 in less than 1 hour on one day because of this close together thing. I also could afford to go off do other stuff like the kills (which took me always much longer than fates), or just sit back and read a book because I could predict when it would likely spawn rather well.