It's amazing what some are able to gain from just one pass. I've been amazed at myself. I did a book called "Battlefield of the Mind" in around 45 mins tops. It was fun!
Depending on the complexity of the texts, your knowledge of its origins, and your previously developed skills as primarily a regular reader, it will take more or less time to get into the "groove" of being able to smoothly go through the system.
I remember when I was learning, and quite frankly I STILL have more to learn about the system, but I believed I would be able to get all of the book. And I did. Some say seeing is believing, but truthfully, its believing is seeing. Then for about 2 weeks, my parents and my brother had convinced me that I wasn't getting all that I needed from the book.
Then, I tried using it in my science classes, and said you myself: "It doesn't matter what anyone says. This is possible. This is not that far to reach. I'll get better all the time."
Then I went through a chapter, did a worksheet, and whizzed through it in under 3 minutes. Comes back with a grade of. . .
*GASP.* A 97! *Starts dancing around the room.* The following papers would also be A's.
Then I learned the reason for failing many of the tests on these books. The questions, at least a little bit over half of them were irrelevant to the story/purpose of the book. Merely insignicant details about the entire plotline, character development, etc. I would have to make multiple passes.
For me, I prepare, PR, then skitter through tests, followed by reading some of the last questions in a few of the problems in various parts when test taking.
I forget what I was meaning to talk about. . . Kinda trailed off there. . .