As an outsider;
A supplier supplies a product.
He insists the user selects the same shade/batch number to avoid tolerance issues in his production process
He does this.
The shade batch turns out not to match.
What more can the tiler/user do???????????????
Simply stating "no responsibility for mismatch can be accepted after fixing" does not absolve the supplier of his responsibilities, and all the end user can be expected to check. It will not stand up if challenged, you buy a red tile, you have a right to get a red tile not pink or claret, the batch/shade No is designed purposely to ensure this.