[quote=@Beloss]
Im banging my head against the wall here with Thomas Edison, who is said to have all E rank stats because of his young age, and Li Shuwen, who is even younger and has A B and C rank stats.
[/quote]

Probably different types of expertise. Wouldn't expect a businessman who has no involvement with mystery to accommodate well to the class system. Li on the other hand has documented supernatural techniques and renowned kung fu mastery, and considering kung fu can make you insanely superhuman even in the modern age, it makes sense that Li has decent stats. Also Nasu did buff Li Shuwen and made him a master of all martial arts and not just Baji, so I guess that sorta helps.