No idea other than they make up whatever rules they have to suit their agenda at the time. What I do know is WBA highly rank people who beat anyone called Lazlo.
They are utterly meaningless, nobody takes the sanctioning bodies rankings seriously. They are just a reflection of which promoter has the closest ties to that organisation and who's given out the most bribes. If you try and look at the rankings seriously it simply baffles how they rank the fighters where they do. For example IBF ranks Parker over Joshua even though Joshua's beaten Parker, Joyce isn't ranked by the WBA but has Dubois ranked number 1, lol.
Let me know when you figure out the WBA gold belt and what it means, it has baffled me for its existence. Basically what everyone said, the orgs have criteria but they can change it and make exceptions as they wish. One of the times this came back to bite them was when Gracciano Rochigianni almost sued the WBC out of existence.
Lineal title is what matters & the WBC diamond spaghetti association pasta belt sponsored by CocaCola™
I don’t think of them as rankings of resume or ability, but more like a queue to face the champion. I think that’s closer to what they actually are.