It was mentioned in an early chapter that since Ricardo is so invincible, all the other boxers are fighting it out in the other organization. If there's only 2 major organizations, then Billy is the champion of that one, which makes the unbeaten feat even greater.
Of course, it's all an "informed ability" thing with little real build-up, so I understand the sentiment of @darekpawlo
i really am glad ippo is properly displaying a lot of different popular and even modern boxing stances, seeing the philly shell in ippo is quite nice to see since we've seen the mayweathers use it their entire career