Agree with that. I still passed CAA exams 12 of them till now first time, but I noticed they are changing the questionbanks. It is quiet annoying. Ofcourse you have to have good book knowledge, because that you will need in interviews, but even with that its hard to score above 90. I can tell you, at home I scored all the time way above 90, but exams below 90. Even had Rnav exam lately. 66 questions. 16 of the questions ive never seen.
So what I try to say. Maye sure you read the book well. First do questions to see where focus is on. Because you dont have to know every letter in the book. Just have to know how things work.
So good luck, but take ur time, because of changing QB.