Enforcement Rules of the Income Tax Act Article 55-1

When an incorporated profit-seeking enterprise conducts alternative computation of its profit-seeking enterprise income for the first-half year in accordance with Paragraph 3, Article 67 of the Act, one half of the expenses or losses based on the whole year that may be subtracted according to the Act shall be subtracted.Computation of the provisional tax paid under Paragraph 3, Article 67 of the Act shall be handled in accordance with Article 40 of the Act.
中文原文 所得稅法施行細則第55-1條
公司組織之營利事業依本法第六十七條第三項規定試算前半年營利事業所得額時,其依本法規定以全年為基礎得減除之費用或損失,應按半數減除。
本法第六十七條第三項暫繳稅額之計算,應依本法第四十條規定辦理。

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