Legal analysis: the calculation formula of customs tax standard is ad valorem: tax payable = duty paid price × tariff rate; The calculation formula of specific tax is: tax payable = quantity of goods × unit tax. After the customs examines and determines the dutiable value of import and export goods, the taxpayer may request the customs in writing to make a written explanation on how to determine the dutiable value of import and export goods, and the customs shall make a written explanation to the taxpayer.

Legal basis: People's Republic of China (PRC) Tax Collection and Management Law.

Article 1 This Law is formulated with a view to strengthening the administration of tax collection, standardizing tax collection, safeguarding national tax revenue, protecting the legitimate rights and interests of taxpayers and promoting economic and social development.

Article 2 This Law is applicable to the collection and management of various taxes collected by tax authorities according to law.

Article 3 The collection, suspension, reduction, exemption, refund and supplementary payment of taxes shall be carried out in accordance with the law. Where the State Council is authorized by law, it shall be implemented in accordance with the administrative regulations formulated by the State Council.

No organ, unit or individual may, in violation of the provisions of laws and administrative regulations, arbitrarily make decisions on tax collection, suspension, tax reduction, exemption, tax refund, overdue tax and other decisions inconsistent with tax laws and administrative regulations.

Article 4 Units and individuals that are obligated to pay taxes according to laws and administrative regulations are taxpayers.

Units and individuals that have the obligation to withhold and pay taxes according to laws and administrative regulations are withholding agents. Taxpayers and withholding agents must pay taxes, withhold and remit taxes and collect and remit taxes in accordance with the provisions of laws and administrative regulations.