The so-called big self-study exam is a national unified exam, while the small self-study exam is a school that issues diplomas with certain propositional rights. The exam time can be discussed, so the exam will be much easier, but the diplomas from the self-study exam are all the same.

You don't have to go to school for the self-study exam, as long as you get your grades when you pay tuition and other hard work.