In which case must we check the customs value of exported goods?

Question: I have a Japanese shipment on the contract showing that both sellers and buyers have completed the declaration, have not sent SI and VGM but now the importer requires to show more Consignee, notify other than byuer is coming. 4 parties, So the contract I need to edit anything? And what do I have to show on Invoice. Packing List and Bill of Lading or show all 4 parties the same documents?
Reply:
In case the importer wants to show another Consignee and Notify party with Buyer as originally agreed in the Contract, this does not affect the export declaration that has completed the customs clearance because the main subject of the declaration. remain Buyer and Seller (Unaltered)
However, to ensure the consistency of the entire set of documents, Invoice, Packing List, Bill of Lading must show the bill to be the payer; The consignee is the consignee and the Notify party on the other. In addition, the buyer and the seller need to sign an extra Annex to agree on the addition of Consignee and Notify not specified in the previously signed two-party purchase contract
SI and VGM, if the enterprise has not sent to the shipping line, after completing the above accurate dossier, it will be sent to the shipping line in accordance with the updated and changed information.