I’m going to assume that the 60-60 bpm is a mixture of two terminologies. I have heard people talk about “60 notes in 60 seconds” or 60 bpm, but never a mixture of the two terms. It could be that it is an old fashioned way of expressing tempo but not the number of times an exercise is to be completed!
It is my understanding that Alfred Cortot was a very brilliant French-Swiss pianist who also taught in a Conservatory in Paris. He was very much a prodigy and a naturally brilliant musician – very intuitive and that was how he taught his students to be. However, sometimes these people aren’t always the best people to pace the rate of development of people who, maybe, are not quite at the same level. I wouldn’t worry then about the pace of the booklet. Getting what you can out of the exercises is more important. You could trudge through the exercises monotonously but unless it’s making a distinct difference to your technique, it will not be time well spent. Perhaps when you have mastered the techniques, you will be able to go through the whole set of exercises in 15 minutes.
I use Hanon for finger exercises from time to time, but I only really dip into the exercises that are relevant to what I need at the time. One exercise from Hanon is plenty when taking your development of technique seriously. As Hanon points out, speed and completion are not the important things here, but rather the technique behind the exercises!