Can HS code on certificate of origin be different from custo

Hello, I would like to ask, your side of China and South Korea FTA certificate of origin on the HS code can be made and our customs declaration HS code is not the same? Customers require that their HS code be shown on the certificate of origin, and our customs declaration is in accordance with the HS code of normal products. Now we need to provide a customs declaration form when we go to our local Commodity Inspection Bureau to handle FTA certificate of origin. Because the HS code is inconsistent, we can't apply for it. If you can operate here, you can directly ask for a copy.