Show > Tell
It's a basic tenet of writing.
Hara will write statements, opinions and views expressed in the manga that don't necessarily line up with what happens or the stats he comes up with in supplemental material.
Isn't relying on the stat system Tell > Show though?
Also, the stat system is pure garbage. The worst one is Shouheikan vs Wategi. Both have STR 91, result is a neg diff fight.
Let us also not forget Great General Gokei having the same Experience rank (B) as fucking Kaine. Kaine isn't even a General. Lel.
Shou Mou was strong, but you can and should pretty much ignore the absurd hyperbole around him, and that goes for everyone else in the manga - whether it's someone we know like Ri Boku or Mou Bu, or someone yet to be introduced in full like Shi Ba Shou and Kou En.
Is it absurd hyperbole though?
At the time that this was said of Shoumou, which
active Zhao General would beat Shoumou for the title of "strongest offensive power of Zhao"?
Renpa and his subordinates had left Zhao.
Gyou'un was in retirement.
Shibashou and his subordinates refused to fight.
Bananji was only ever deployed in Ganmon and possessed little renown.
Who else is there?
Titles like "best" and "strongest" are comparative terms. A person can technically be bad at something and still be "the best" simply by being better than the competition. Shoumou was better than the competition he had (e.g. Mangoku).
Besides, we should all remember that Shoumou (and all the other Bayou Zhao Generals) were deliberately chosen and sent to fight against Ouki.
Yeah, Ouki made Shoumou look like a scrub but would anybody in their right mind actually send a scrub to fight against Ouki of all people?
Shoumou was hella strong and was one of the best active Generals that Zhao had at the time. Ouki was just a whole level stronger.