The costs of appeal are assessed against the Plaintiff.

1. Article 52 of the Framework Act on National Taxes provides that "When the head of a tax office appropriates or pays a national tax refund pursuant to the provisions of Article 51, he shall add an amount calculated according to the interest rate prescribed by the Presidential Decree (hereinafter "additional payment on national taxes") to the national tax refund taking into account the period from the day following the day specified in the following subparagraphs until the day when the refund is appropriated or the payment decision is made, and the deposit interest rate at financial institutions. Accordingly, Article 30 (2) of the Enforcement Decree of the Framework Act on National Taxes provides that the above interest rate shall be three percent (10.95%) per day for the national tax refund of 10,000, but Article 30 (2) of the Enforcement Decree of the amended on December 29, 200 (from April 1, 2001) of the Enforcement Decree of the National Tax Act provides that the interest rate on the national tax refund shall be applied to the portion of the national tax refund of national tax at an average of 15 years maturity of a commercial bank (201.314).

According to the provisions of the relevant laws and regulations, in calculating the additional payment on the refund of national taxes to be paid by the defendant to the plaintiff, it is clear that the interest rate on the additional payment on the refund of national taxes as stated in each notice should be applied after the enforcement date of each notice, and the additional payment on the refund of national taxes for the period after the enforcement date of each notice given by the plaintiff to be paid by the defendant is incurred only due to the enforcement of each notice in the judgment. Thus, even if the plaintiff received the additional payment on the refund of national taxes for the period after each notice was issued by the plaintiff, the additional payment on the refund of national taxes for the period according to the interest rate lower than the previous interest rate, it shall not be deemed null and void as it goes against the principle of prohibition on retroactive taxation (each notice in the judgment is asserted to the effect that

The decision of the court below to the same purport is just, and there is no violation of a misapprehension of legal principles as to retroactive legislation as alleged in the grounds of appeal.

2. Each public notice in its holding functions as a legal order with external binding force in combination with superior statutes, the Framework Act on National Taxes, the Enforcement Decree of the same Act, and the Enforcement Rule of the same Act, and statutes are immediately applicable after the enforcement date, barring any special circumstance, each public notice in its holding is subject to the new public notice after the enforcement date of each public notice, unless there are special circumstances, even though each public notice in its supplementary application does not provide that "this public notice shall apply to the portion for which the period has passed after the enforcement date of each public notice." Therefore, the application of a new public notice in its holding after the enforcement date cannot be deemed as a legitimate legal principle and thus, separate delegation is not necessary (the foregoing supplementary provision, contrary to the assertion in the grounds of appeal, there is room to view that the previous public notice applies the interest rate set in the previous

The court below's rejection of the plaintiff's assertion to the same purport is justified in its conclusion, although there are some inappropriate parts in its reasoning, and there are no errors in the misapprehension of legal principles as to the scope of delegation of superior statutes as alleged in the ground of appeal.

3. The Plaintiff’s expectation that the additional payment on the refund of national taxes would only be made in accordance with the provisions of the statutes and be different from the interest on deposits that accrue according to the agreement between the parties. The Plaintiff’s expectation that the legislation on the rate of calculating the additional payment on the refund of national taxes would not be revised is without any grounds, and it cannot be viewed as contrary to the principle of trust protection or criticism on the ground that this was not satisfied. The argument in the grounds

4. Therefore, the appeal is dismissed, and the costs of appeal are assessed against the losing party. It is so decided as per Disposition by the assent of all participating Justices on the bench.