Where does it say Zoro poured ALL his haki into his swords? Where does it say Zoro would go ALL OUT with his haki?
The keyword here is "keeps exuding his haki" which means Zoro poured SOME of his haki into his swords meaning there are still some haki left in Zoro's haki reverse.
So this debunks that Zoro poured ALL his haki into his swords.