The school is for the college entrance examination and the language school is for getting a visa. Students who only need a visa and don't need to go to college, such as those who just want to learn Japanese or who only consider special schools and don't consider going to college, generally don't apply to school.
Most students who want to enter the university apply to the school, otherwise many students don't even know how to enter the university.
There are two kinds of tuition fees: single course and package. But it is the same as McDonald's. It is definitely not as cost-effective to buy a single course one by one as to buy a set meal.
Specifically, it is better to go directly to understand. There are telephones and mailboxes on the website, and several cities in China seem to have offices.