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

The defendant, 17,523,898,568 won and its amount to the plaintiff corporation A.

1. The reasons why the court should explain this part of the basic facts are the same as the entry of “1. Basic Facts” in the judgment of the court of first instance, except for the following parts, and therefore, they are cited in accordance with the main sentence of Article 420 of the Civil Procedure Act.

In the 7th judgment of the first instance court, the "this court" in the 5th judgment shall be deemed to be the "first instance court".

2. The reasons why the plaintiffs' assertion in this part is stated are the same as the entry of "the summary of the plaintiff's assertion" in the judgment of the court of first instance. Thus, this part is cited in accordance with the main sentence of Article 420 of the Civil Procedure Act.

3. Determination on the claim for indirect construction costs incurred by extension of the construction period

A. (1) According to Articles 20, 23, and 26 of the General Conditions in the instant case, which form the terms and conditions of the instant contract, the other party to the contract (contractor) may file an application for the adjustment of the contract amount if the contract period is extended due to an event not attributable to the other party to the contract, and the contracting officer shall adjust the contract amount to the extent that the modified contract does not exceed the actual cost according to the terms and conditions.

(2) The Defendant asserts that the obligation to adjust the contract amount under Article 23 of the General Conditions of this case arises in addition to “in the event of an increase or a decrease in the quantity of construction work in the design modification,” and that the contract amount adjustment obligation does not occur for the reason of extension of the construction period, even if the construction period was changed together, in the event that the cause of the change in the contract is a change in the design, such as the first, second, and third changes in the contract in this case.

(3) In a case where the construction period is extended together with the modification of the contract, due to an increase in the quantity of construction work in the design modification, such extension shall also be extended.