The part of the judgment of the first instance, including the claim extended in the appellate trial, against the plaintiff A, is as follows.

1. Facts of recognition;

A. As C died on November 1, 201, on May 31, 201, the Plaintiffs, co-inheritors, filed an application for annual installments for KRW 450,000 among inheritance tax by filing a return on the inheritance tax base with the head of Yongsan Tax Office on May 31, 2012, and the head of Yongsan Tax Office permitted annual installments on December 12, 201.

Accordingly, the plaintiffs paid inheritance tax and additional dues on five occasions as follows.

Plaintiff B (A) 10,00,000,000 won for annual installments (A) 18,000,150 won on February 27, 2014, 108,000,150 won 14,400,120 won on March 2, 2015, 104,400,120 won for 104,400,120 won on February 26, 2016, Plaintiff A 10,80,000,000 won for annual installments (A) 10,80,800,000 won for 10,80,000,000,000 won for annual installments 18,000,000,000 won for 28,0000,719,708,000 won for 19,78,009, 307 won for 19,20708 won

B. The above additional dues for annual installments are calculated by uniformly applying 4.0% per annum, which is the interest rate on the additional payment for annual installments, stipulated in Article 19-3 of the former Enforcement Rule of the Framework Act on National Taxes (amended by Ordinance of the Ministry of Strategy and Finance No. 320, Mar. 1, 2013)

Meanwhile, according to the amendment of the above Enforcement Rule, the interest rate on the additional payment on the refund of national taxes during the payment period of the plaintiffs gradually lowered to 3.4% per annum, 2.9% per annum, 2.5% per annum, 1.8% per annum, and 1.6% per annum. The difference between the additional payment on annual installments calculated by applying the amended interest rate in each payment period and the additional payment on annual installments paid by the plaintiffs is 11,492,264 won (=Plaintiff A8,225, 653 won).

[Reasons for Recognition] A without dispute, Gap evidence Nos. 1-3, Eul evidence No. 6, the purport of the whole pleadings

2. Determination

A. The additional dues under Article 72 of the Inheritance Tax and Gift Tax Act (hereinafter “Inheritance Tax Act”) are a kind of incidental tax imposed by an agreement according to the extension of the time limit for payment of inheritance tax. In the case of a taxpayer who pays inheritance tax in installments with the permission for annual payment by annual installments, the additional dues shall be paid in lump sum.