1. The plaintiff's appeal and the additional selective claims filed by this court are all dismissed.

2. After filing an appeal.

On February 2, 2012, the Plaintiff entered into a subcontract with the Defendant for each of the instant apartment construction contracts (hereinafter “the instant apartment contract”) during the contract period of 10,257,157,00 won, and the construction period from February 3, 2012 to May 15, 2014 with respect to the instant apartment construction works among the “construction works for the 3rd East East East East Eastern Housing Development and Improvement Project Association” contracted by the Defendant for the construction works for the 3rd East East East East Eastern Housing (hereinafter “the instant apartment construction contract”). On May 7, 2012, the Plaintiff entered into a subcontract with the Defendant Co., Ltd., Ltd., and the Defendant et al., under the contract with the Korea National Oil Corporation for the construction works for the 10,175,000,000 won, and each of the instant construction contracts from the Korea National Oil Corporation (hereinafter “the instant new apartment construction contracts”) to the construction period of 131,2012.

Article 3 of the subcontract agreement (main sentence) of each construction contract of this case is as follows.

Article 3 (Construction, etc.) (1) The plaintiff shall perform the construction work in accordance with the terms and conditions of this contract and design documents (including construction specifications, design drawings and site descriptions: Provided, That in cases of the total unit price contract, the calculation sheets shall be included, and the forms shall apply mutatis mutandis to the rules established by the Ministry of Finance and Economy).

(2) The plaintiff shall prepare a schedule for construction work and obtain approval from the defendant without delay after concluding the contract, and submit a statement of particulars to the defendant without delay.

With respect to the instant apartment construction contract, ① on June 22, 2012, the construction cost was changed to KRW 10,336,644,220; ② the construction cost was reduced to KRW 99,928,240 on January 11, 2013; ③ the construction cost was reduced to KRW 953,672,00 on July 30, 2013; ④ the construction cost was increased to KRW 570,130,00 on December 9, 2013; ⑤ the construction cost was increased to KRW 570,130,000 on December 9, 2013; ⑤ the construction cost was reduced to KRW 570,130,00 on February