Answer: According to the \"State Administration of Taxation on the issuance of\" Production enterprises Export Goods exemption, credit, tax refund Management Procedures \"(trial) Notice (State tax Fa [2002]11) document article 2, paragraph 1 of the production enterprises export goods exemption, credit, tax rebate shall be calculated according to the export goods FOB, export goods rebate rate. Free on board (FOB) of export goods shall be based on the FOB on the export invoice. If the transaction is made at other prices, the freight, insurance, commission, etc. allowed to be deducted from the export sales income according to the accounting rules shall be deducted. If there is a difference between the declared amount and the actual amount paid, it will be adjusted in the next tax refund declaration. If the export invoice cannot truthfully reflect the FOB price, the enterprise shall declare the exemption, credit and refund according to the actual FOB price, and the tax authorities shall have the right to verify the tax in accordance with the relevant provisions of the Law of the People's Republic of China on the Administration of Tax Collection and the Provisional Regulations of the People's Republic of China on Value-added Tax.