Exemption of profit-seeking enterprise income tax for foreign international transportation enterprises in accordance with Subparagraph 20, Paragraph 1, Article 4 of the Act is limited to the cases where there is a reciprocal tax exemption clause in the tax treaty signed with the R.O.C. government or there is consent to reciprocal tax exemption by exchange of diplomatic letters, and where the Ministry of Finance has approved the practice of such tax exemption.