It's quite clear Oda doesn't want to solidify Jinbe's position in the crew strength wise yet. That's why he's leaving the possibility of Who's Who beating Calamities up in the air. He's sending mixed signals on purpose.
Regardless of whatever interpretation of WW's strength, Land Jinbe mid diffing WW, even if a "YC4", easily puts him Top YC level. He might even rival/surpass King & co, when in water.