1. The judgment of the court of first instance is modified as follows.

The defendant shall pay to the plaintiffs KRW 3,517,580,778 and the defendant shall pay for the above.

1. Facts of recognition;

A. 1) The Plaintiffs constitute a joint supply and demand organization on November 27, 2003 and the Defendant and the “D Corporation” (hereinafter “instant construction”) (hereinafter “instant construction”)

(1) The contract amount of the construction work is set at 73,504,915,000 won, and on April 4, 2008 (52 months from the date of the first commencement) and the contract amount for the construction work (hereinafter “instant contract”).

(2) The main contents of the instant case are as follows among the “general terms of construction contract” incorporated into the content of the instant contract.

Article 20 (Adjustment of Contract Amount Due to Modification of Design) (1) If there occurs an increase or decrease in the volume of construction, such as an increase or decrease in the method of construction in a design modification, or in the quantity of input materials, the contracting officer shall adjust the contract amount according to

(2) Notwithstanding the provisions of paragraph (1), where an ordering agency requests a design change (including cases due to reasons not attributable to a contractor; hereinafter the same shall apply), the unit price of increased quantity or new item shall be determined by mutual consultation between the ordering agency and the counter-party within the scope of the amount calculated by multiplying the unit price calculated as at the time of the design change by the successful tender rate.

(4) The ratio of increase and decrease in the contract amount referred to in paragraphs (1) and (2), such as indirect labor expenses, industrial accident insurance premium and safety management expenses, and general management expenses and profits shall be the ratio of indirect labor expenses, such as the ratio of industrial accident insurance premium and safety management expenses, and the ratio of general management expenses and profits on the calculation sheet, but such ratio shall not exceed the ratio determined

(7) Where an order-placing agency adjusts a contract amount under paragraphs (1) through (6), it shall adjust the contract amount within 30 days from the date of receiving a request from the other party to the contract for the adjustment.

In such cases, where it is inevitable, such as delay of allocation of budget, it shall be consulted with the other party.