1. The Defendant’s KRW 1,619,320,896 to the Plaintiffs and KRW 201,00,000 among them, shall be from March 30, 2017; and KRW 1,418,320.

1. Facts of recognition;

A. 1) On February 11, 2009, the Defendant entered into a contract for the instant construction works (hereinafter “instant construction”) with D Nowon-gu Construction Work on February 11, 2009

(2) The Plaintiffs constituted a joint supply and demand organization (hereinafter “instant joint supply and demand organization”) with the representative of Plaintiff A Co., Ltd. (hereinafter “Plaintiff A”). The share ratio of the joint supply and demand organization of this case is 50%, Plaintiff B Co., Ltd. (hereinafter “Plaintiff B”) 33%, and Plaintiff C Co., Ltd (hereinafter “Plaintiff C”) 17%.

The joint contractors of this case participated in the bidding of the construction of this case, and the defendant selected the joint contractors as successful bidders on April 2, 2009.

3) On April 27, 2009, the instant joint contractor entered into a contract for construction works with the Defendant for the total construction period of KRW 59,589,406,00 with respect to the instant construction works, and with respect to the construction works from April 27, 2009 to April 25, 2014. [General Conditions for the Contract for Construction Works] Article 20 (Adjustment of Contract Price due to Modification of Design) (1) The contracting officer shall adjust the contract price according to the following standards if an increase or decrease occurs, such as a change in the method of construction of a design, a change in input materials, etc.

The term "new items" shall be referred to as "new items"

(i)The unit price shall be at the time of the modification of the design (where the design drawing needs to be modified, when the agency awarding the contract determines the modified drawing, and where the modification of the design drawing is not required, when the parties to the contract agree in writing.