You can think that a boxing world ratings is exactly, but never it is. Look at this example, at random, of may 1971, in the Junior Welterweights (or Super Lightweights or Light Welterweights or ...) and the differences in the "official" ratings:
WORLD BOXING ASSOCIATION
WORLD CHAMPION
Nicolino Locche, Argentina
-1----Bruno Arcari, Italy
-2----Joao Henrique, Brazil
-3----Domingo Barrera Corpas, Spain
-4----Enrique Jana, Argentina
-5----Rene Roque, France
-6----Bunny Grant, Jamaica
-7----Adrian Davis, United States
-8----Lion Furuyama, Japan
-9----Juan Aranda, Argentina
10----Eli Yares, Philippines
WORLD BOXING COUNCIL
WORLD CHAMPION
Bruno Arcari, Italy
-1----Joao Henrique, Brazil
-2----Adolph Pruitt, United States
-3----Eddie Perkins, United States
-4----Bunny Grant, Jamaica
-5----Pedro Adigue, Philippines
-6----Nicolino Locche, Argentina
-7----Enrique Jana, Argentina
-8----Carlos Hernandez, Venezuela
-9----Rene Roque, France
10----Adrian Davis, United States
In that times there weren't the International Boxing Federation or the World Boxing Organization or the near of 30 others "officials organizations" of boxing, but the chaos was playing against boxing. WBA, WBC, IBF, WBO, and all others you thinks, are necessary for boxing? I thinks: no!