Regulations Governing Customs Clearance Procedures for Air Express Consignments Article 14

Express delivery enterprises or Customs brokers shall not make separate declarations to Customs for a single importation of express consignments. Nevertheless, separate declarations shall be accepted where the aggregate Customs value does not exceed the ceiling eligible for duty exemption proclaimed by the Ministry of Finance pursuant to paragraph 2 of Article 49 of the Act, or, even though the aggregate Customs value exceeds the said ceiling, declarations have been voluntarily made and the duties duly paid.A single importation of express consignments referred to in the preceding paragraph means all the express consignments shipped from one consignor to one consignee by the same flight.
中文原文 空運快遞貨物通關辦法第14條
快遞業者或報關業者不得將同批進口快遞貨物分開申報。
但完稅價格合計未超過關稅法第四十九條第二項規定經財政部公告之免稅限額,或雖超過限額而主動申報繳納進口稅費者,不在此限。
前項所稱同批進口快遞貨物,係指同一發貨人以同一航(班)次運輸工具發送給同一收貨人之快遞貨物。

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