1. Defendant Sejong-do’s 561,522,248 Won and its related 6% per annum from April 6, 2019 to January 8, 2021.

1. Basic facts

A. 1) On September 9, 2004, the Public Procurement Service under the Defendant’s Republic of Korea published a public tender for construction works with respect to FRoad Packing Works (hereinafter “instant construction works”).

2) On December 29, 2004, the Plaintiffs organized a joint supply and demand entity (share ratio: Plaintiff A: 50%, Plaintiff B Co., Ltd., 20%, Plaintiff C10%, Plaintiff E Co., Ltd., 10%, Plaintiff E Co., Ltd., 10%, and hereinafter “instant joint supply and demand entity”) that represents Plaintiff A Co., Ltd. (hereinafter “Plaintiff A”) as the representative company, and determined as the successful bidder by participating in the said bidding; and thereafter, on December 29, 2004, the Plaintiffs entered into the instant construction project with Defendant Gyeongnam-ro, the contract amount, KRW 1,349,00,000, and the date of commencement as of December 30, 2004, and the construction period from January 30, 2005, to 30 days after the commencement of the construction period, and entered into the construction contract with each of the instant entities as the total construction period of KRW 130,219,200.

3) Of the general terms and conditions of the construction contract contained in the instant contract (established by the Accounting Rules 2200.04-104-12, April 6, 2004; hereinafter “instant general terms”) related to the instant case are as follows.

Article 20 (Adjustment of Contract Price due to Modification of Design) (1) A public official in charge of contracts shall adjust the contract price according to the following standards if there occurs an increase or decrease in the volume of construction, such as a change in the method of construction in design modification, or a change in input materials:

1. The unit price for the increased or decreased volume of construction works shall be the unit price per contract;

(B)

2. Items or cost items that are not written calculation details (including where the performance, standard, etc. is different even for the same item);

The unit price for a new item (hereinafter referred to as "new item") shall be determined at the time of design modification (where the design is to be modified, when the agency awarding the contract has determined the modified plan.