Commander level almost definitely does not exist outside of fan perception.
YC1 level does not exist.
YC2 level does not exist.
YC3 level does not exist.
These ARE USEFUL as general levels in tier lists. BUT
Stop using them as the end-all be-all in VS-battles. "X would win because Y is YC_" or "Y would lose to X because X is YC_" is lazy and disrespects the wonderful (yes, wonderful) fuzziness of One Piece.