Hi Pongpan,
There are three exam modes in the Simulator: timed, learning, and real exam mode.
The real exam mode features the 8 exams in the Simulator. It is timed for 4 hours straight with 200 questions per exam so it mimics the real exam.
Both the timed and learning mode generates the quizzes from the 1600+ pool of questions also used in the 8 aforementioned exams in the real exam mode. They are customizable according to the topic (either ay of the 10 knowledge areas or of the 5 domains), and number and kind of questions you want to take in the session. These modes are designed so users can focus on certain areas/topics for improvement and/or to accommodate their schedule. This comes in handy when, say, you only have 1-hour lunch break and you want to spend it practicing since the real exam mode doesn't really allow you to pause a session.
To answer your questions:
1. I understand that if I select timed and learning quizzes, the question will take from all 8 PMP exam. Am I right?
-Yes, you are right.
2. The learner should be able to select timed and learning quiz for specific PMP exam (example PMP exam 5) so he/she can do the 'real mode' on the other exam.
-This isn't true. If the learner would want to take the real exam mode on a specific PMP Exam then he/she could just click on the mentioned exam (i.e. exam 5).
Hope this clarifies your concern.