[2022] Why does Jinan have only 8 flaks while Sejong has 10?

AA values do technically follow a logical pattern to begin with, and then AA values can be tweaked when deemed necessary on a ship-by-ship basis.
That accounts for most of the things Mouse listed here where you may see small inconsistencies in the pattern.

Actually, @Ahskance and myself have been going over AA values for about a week now. We're in the process of making a few recommendations