Zoro isn't using Foxfire Style
He isn't using Adv CoC neither FOR NOW
He literally did the same thing you can see here
No CoC coating in the first and second panel, adds CoC coating in the third panel
After using CoA Flow, he unleashed also CoC
Basically Zoro is NOW fighting at full power (almost... no Ashura)
Likewise
You can clearly see there was NO COC there
No delusion
And that there clearly starts to be COC here
Likewise no delusion also here, it's CoC
Showing that Zoro will fight for real, FROM NOW ONWARDS
It's stupid to think that he was going at his max before, and it's likewise stupid to think he isn't going at a good portion of his max now
He is now in full King of Hell Style
Adv CoA (flow) + Adv CoC (coating)