Enforcement Rules of the Foreign Trade Act Article 17

In accordance with paragraph 1 of Article 21 of the Act, exporters/importers shall pay trade promotion service fees within fourteen days of the date that customs issued the certificate of payment.Regarding collection of the aforementioned trade promotion service fees, customs shall include the fees with the certificate of payment and import duties for imported goods to be collected simultaneously; for exported goods, the fees shall be collected after customs clearance and shipment.
中文原文 貿易法施行細則第17條
依本法第二十一條第一項規定應繳納之推廣貿易服務費,出進口人應自海關填發繳納證之日起十四日內繳納。
海關收取前項推廣貿易服務費時,其屬進口貨品者,併入稅款繳納證與進口稅捐同時收取;其屬出口貨品者,於運輸工具結關開航後收取。

English translation for reference only; the Chinese text prevails. Not legal advice.