For example, if the pre-defined account coding scheme in the postal system is "4-2" secondary coding, the total length of the primary account coding and the end-level detailed account coding should be 6 digits. Among them, there are 4 first-level disciplines and 2 in two disciplines. When we use this scheme to add accounts, we must also follow the predefined coding scheme.

Take the bank deposit account as an example. If you set the secondary code of "4-2", then we can increase the subject of bank deposit to1002; Increase the secondary detail account to 10020 1. Here, the total length of 10020 1 is 6 bits. Where 1002 is a first-class subject with 4 digits, and 0 1 is a second-class code.

So there won't be such a profitable situation as you said.