I've read the PMBok 4th ed, and Rita's 6th ed and took her quizzes in the book.   When I read just the PMBOK, I passed her tests at about 75%.  Then weeks later, I start reading her book and take the quizzes and get 80% consistently.  Also, her demo CD for PMFASTrack, I got 80% on 25 questions the first time.    I took another sample test on the internet (5 questions) and got 100%.

So I am getting confident, UNTIL I take the PMZilla questions and consistently score 30%.

What's going on?

Thanks