That’s correct. (It’s also fascinating for that reason. They converted the class

That’s correct.
(It’s also fascinating for that reason. They converted the classes and occupations to what elsewhere would be expressed (as in the west) as a military hierarchy with attendant duties and responsibilities. And while it’s not been adaptive or innovative (a least since 100ad) it’s functioned almost flawlessly otherwise.)
I came to understand one of the reasons for class conflict is the failure to retain rules for, expectations for, and respect for the classes, by the pretense there no longer were classes. And this created negative feedback for the lower classes, because instead of doing moral duty and gaining respect for it, they are somehow ‘less or left behind’. (Which isn’t good for anyone.)