A tier is a subjective thing: I said King is markedly stronger than Queen, which I think was made quite clear.
That is not true for admirals.
Marco merely said it was tough to fight both of them, wanted criminals above a billion (as Jack, btw). Never said anything specific.
Using that to argue King ~ Queen is like using the monster trio statement (or the wings of the PK) to argue that Zoro ~ Sanji, which I hope it is sufficient on its own and doesn't need my observations on it.
In the manga, we saw that Jack, King and Queen are in the same group, but Queen is markedly stronger than Jack (and has a higher rank) as King is compared to Queen.
That is further proved by the fact that in almost all other cases we saw the exact same dynamic.