hi Sumit, you may get a combination of both, it really depends on how random the questions are chosen. I dont really know how the randomization works, but all will get equal questions by difficulty/subject.
We hope that the mock questions are a little bit harder than the real exam, but I wouldn't recommend that you add 20 points! In other words you should be closer to the official pass rate before you feel comfortable.
Spot false dilemmas now, ask me how!
(If you're not on the edge, you're taking up too much room.)