Taking two weak examples when we have more than 50 strong ones, then it's easy. Tobiroppos' strength level is similar to that of the current Straw Hats, apart from the 4 strongest, and both groups actually have similar levels.
And if we take the yonkous, all of which have very high rewards and have good indicators of their strength or dangerousness, the only exception is Buggy due to information asymmetry.
Reward is, at least in 95% of cases, a good signal of strength level. It's not decisive, as I said, because as you said, there are exceptions, like Chopper and Robin as a child.
