Class a workers, like civil servants, are guaranteed income through drought and flood. Class B workers are contract workers, better than temporary workers. It is difficult to get up when the appreciation reaches a certain level. B-level workers are ok, but now it is basically difficult to become A-level workers.

Everyone who goes in starts working at the grassroots level, and so do the new class A workers. There is not much difference. Being a Class B worker in the post office should be a good job now, and the salary is ok.