1. The Plaintiff (Counterclaim Defendant) paid KRW 342,933,306 to the Defendant (Counterclaim Plaintiff) and its related amount from January 12, 2019 to December 17, 2020.

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. Basic facts

A. 1) On April 27, 2015, the Defendant entered into a construction contract with the Plaintiff on April 27, 2015, the building “D” on the ground C of the Seo-gu Busan Metropolitan City (hereinafter “instant building”).

) New construction works (hereinafter “instant construction works”)

(3),530,594,00 won for contract, the date of commencement, May 31, 2015, and May 31, 2016, and the date of completion of the relevant completion of the project (hereinafter referred to as “the first contract”).

(2) On May 25, 2016, the Plaintiff and the Defendant concluded an amendment agreement to extend the construction period to July 20, 2016. On July 19, 2016, the Plaintiff and the Defendant concluded an amendment agreement to extend the re-construction period to August 20, 2016.

3) On December 1, 2016, the Plaintiff and the Defendant entered into a contract for the additional construction of the instant building (hereinafter “additional contract”).

In preparing the contract amount, the contract amount was determined as KRW 173,150,970 (value 166,746,247 value-added tax 6,404,723 value-added tax 6,404,723 value-added tax 16,247 value-added tax) and December 1, 2016 as of the commencement date, and December 26, 2016. The above additional contract was accompanied by a statement of the statement of the change in the recognition of the owner and the statement of the completion date of completion of the project. The sum of the increase and decrease in the above statement is KRW 16,746,247, and KRW 16,70. (b) The building in this case was approved for use and payment of construction cost for the building in this case) under the ground and the 12th floor and September 12, 2016.

The underground first floor of the building of this case is a machine room and parking lot, and the first to fourth floor of the ground, and the second-class neighborhood living facilities of this case, the fifth to 12th floor of the ground are apartment buildings.

2) The Defendant paid the Plaintiff the construction cost of KRW 3,530,594,00 according to the first contract, and KRW 173,150,970 according to the additional contract. [Grounds for recognition] The Defendant did not dispute a dispute, and the evidence A of subparagraphs 1 through 5 (including the serial number; hereinafter the same shall apply).

each entry, the result of appraiser E’s appraisal, the purport of the whole pleading

2. The parties' assertion

A. At the time of entering into the first contract, Plaintiff 1 was awarded a contract with the Defendant to construct the instant building up to 12 floors.

However, there is a problem.