Article 19 of the Constitution provides that the people shall have the duty to pay taxes as required by law. And, as we have made clear in our J. Y. Interpretation No. 420, laws relating to tax matters must be interpreted in such a manner as to follow the spirit of the principle of taxation by law and to conform with the legislative purposes of the respective statute by taking into consideration the economic meaning and the principle of equality in actual assessment of tax. The Guidelines for the Audit of Income Taxes on Profit-making-Enterprises issued by the Ministry of Finance on December 30, 1993, are intended to regulate the investigation and review of, and other matters in connection with, final business income tax returns. Under Subparagraph 4 of Article 92 of the Guidelines, payment of overseas commission in excess of five percent must be proved with the production of additional supporting documents, showing therein good reasons for the payment, for the authority*s verification. Item 3 of the Subparagraph 5 sets forth recipients of commissions that are unacceptable for verification purposes, and Item 4 specifies documents required to prove the payment of commissions. These are all clauses on the manner of proving and the requisites for verifying payment of overseas commissions. To deal with the difficulty in investigating into and determining whether payment for overseas commission is actually made in the case of payment declared to have been made locally in New Taiwan dollars, Item 5 of Subparagraph 5 of the same Article of the Guidelines provides that "where an overseas commission is paid locally in New Taiwan dollars, a receipt issued in the name of the overseas agent or distributor must be produced for verification purposes, to the extent that the amount of such commission does not exceed three percent of the selling price of the goods exported." This clause to make three percent of the export price of the goods a line of demarcation was devised by taking as a benchmark the limit set by the authority in charge of foreign exchange control in the past on the percentage for which foreign exchange settlement was allowed without requiring application for government approval. As a result, the evidence that a business entity is required to produce to the tax authority and the degree of proof required will differ, depending on whether the amount of commission payment exceeds the three percent standard. Furthermore, Directive Tai-Shui-Yi-Fa No. 861912671 issued on August 16, 1997, by the Department of Taxation, Ministry of Finance, states that, “where the overseas commission paid in Taiwan by a business entity in New Taiwan dollars does not exceed three percent of the selling price of the goods exported, it may be verified by the tax collection office against the receipt issued in the name of its overseas agent or distributor together with the agreement executed by both parties, and that, where the payment of commission exceeds three percent of the export price, the portion above three percent may be verified provided that the business entity can produce, in addition to the aforesaid receipt and agreement, other relevant documents such as correspondence, telegrams, facsimiles, and photocopies of passports of the foreign personnel visiting Taiwan, together with documents showing that the New Taiwan dollars payment was truly received by its overseas agent or distributor or was deposited into his bank account, e.g., documents evidencing payment in care of someone, by remittance, or for offsetting the recipient*s purchase price in Taiwan, and the documents are found by the tax collection office to be true and correct.” From the above, we conclude that the text of Item 5 quoted above is meant to regulate such technical details as the verification and proof of the commission payment, and is necessary in order to simplify the tax collection operation and to avoid superfluous declaration of overseas commission payment. It does not go beyond the relevant provisions of the Income Tax Act and other laws, nor does it place any additional taxations on the people, and is therefore not in conflict with Articles 15, 19, and 23 of the Constitution. Furthermore, the clause is not contrary to the principle of equality enunciated by Article 7 of the Constitution in specifying a different standard of verification for overseas commission paid in the Taiwan area in New Taiwan dollars from the payment of overseas commissions otherwise specified in the same article by taking into account the differences in factual circumstances, as the portion above the three percent limit may still be verified if additional documents are produced by the business entity.