from hyo's description
its technically a step up
"Zoro's general CoA was strong enough to physically chop up Kaido's scales with a mid-level attack. Asura was strong enough to scar Kaido for life. And no, it did not have visuals of ACoC- he probably just used CoC passively like Luffy in MF."
the scabbards were cutting the scales too
albeit not not the same extent because they cant generate the amount of ap zoro can but they still were
"By feats, portrayal and Zoro's own specialization, his CoA is more potent than Luffy's."
that just implies zoro out of the timeskip would be a stronger coa user than the other two colors of haki
its not really a basis for comparison with the others.