consider your score on an unofficial exam to be an accurate indicator of your true capabilities. What people don't realize, is that these "fake" exams, inaccurate as they may be, are beneficial to some extent. They copy the real exams, word for word, but occasionally making the problem more challenging. As a result, you're subject to much higher material than usual, and that in my opinion can build some worthwhile endurance.
But in regards to your question, yes, PR
exams are significantly more difficult than CB/Real exams.