1. The Defendant’s KRW 78,445,100 and the Plaintiff’s annual rate of KRW 6% from March 17, 2017 to August 13, 2019, and the following.

1. Basic facts

A. On January 23, 2017, the Plaintiff (contractor) concluded a contract for interior works (hereinafter “instant contract”) with the Defendant (contractor) and the Geumcheon-gu Seoul Metropolitan Government on February 28, 2017, stipulating that “The construction site D and the date of commencement: January 23, 2017; and the date of completion of the completion of the construction: February 28, 2017; the construction cost of KRW 164 million (Advance 30%4,9.2 million) within seven days after the contract was concluded; the intermediate payment of KRW 40% within 14 days after the completion of the wall installation; the remainder of KRW 30%; KRW 49.2 million within 14 days after the completion of the examination; value-added tax”).

B. The Plaintiff was requested by the Defendant for additional construction in addition to the construction stipulated in the instant contract.

On February 23, 2017, the Plaintiff sent to the Defendant a written estimate (Evidence A 2-1), which is the sum of the construction cost of KRW 75,335,100 (excluding value-added tax) and the total construction cost of KRW 5,00,400 (value-added tax separate) (Evidence A-2-2).

(hereinafter referred to as the “instant estimate”) . (c) aggregating two estimates.

On March 16, 2017, the Plaintiff completed all of the instant construction works and additional construction works (hereinafter collectively referred to as “instant construction works”).

The Defendant paid the Plaintiff KRW 5,412,00 as the construction price stipulated in the instant contract, KRW 5,412,00,000,000 for the contract deposit on January 26, 2017, KRW 7,2160,00 for intermediate payment on February 20, 2017, and KRW 5,412,00 on March 11, 2017, but did not pay the price for the additional construction.

[Reasons for Recognition] Facts without dispute, Gap 1, 2, 5, 6 and 7 evidence, the purport of the whole pleadings

2. Determination as to the cause of action

A. A. The summary of the party’s assertion 1) The Plaintiff agreed to the construction cost specified in the instant quotation, and thus the additional construction was carried out by the Defendant. The Defendant must pay the Plaintiff the construction cost of KRW 88,369,050 (including value-added tax) specified in the instant quotation. (2) The Plaintiff and the Defendant concluded the instant contract by reducing 23% of the amount specified in the quotation presented by the Plaintiff to the Defendant.

The plaintiff's additional construction cost should also be reduced by 23% from the amount of the estimate of this case.