legal ground
Article 18 of the Regulations of People's Republic of China (PRC) on Import and Export Tariffs
The customs value of imported goods shall be determined by the customs on the basis of the transaction price meeting the conditions listed in the third paragraph of this article, the transportation of the goods before they arrive in People's Republic of China (PRC) and the domestic import sites, and the related expenses and insurance premiums. The transaction price of imported goods refers to the total price actually paid and payable by the buyer to the seller for importing the goods when the seller sells the goods to People's Republic of China (PRC), and adjusted according to the provisions of Articles 19 and 20 of these Regulations, including direct payment and indirect payment.
Article 19
The following expenses of imported goods shall be included in the customs value:
(1) Commissions and brokerage fees other than purchase commissions borne by the buyer;
(two) the cost of the container that is regarded as an integral part of the goods when the customs value is examined and approved by the buyer;
(six) the seller directly or indirectly obtains the proceeds from the resale, disposal or use of the goods after import from the buyer.