The part against the Defendant is reversed, and that part of the case is remanded to the Seoul High Court.

1. As to the additional construction cost of the remainder of the construction, excluding the part of the volatilen Center

A. According to the reasoning of the lower judgment on the grounds of appeal as to whether to grant the claim for additional construction cost, the lower court appears to have scheduled the adjustment of construction cost resulting from design modification in principle by introducing various provisions on the premise of the adjustment of construction cost in the event of subsequent modification in the contract documents related to the second construction contract in the future. On the other hand, the lower court determined that the Plaintiff may claim additional adjustment of construction cost in accordance with the scope of the instant construction contract on the ground that Article 2(1) of the construction contract does not allow the increase or decrease in construction cost in the case of “a modification in the function required or upon the Defendant’s request” in the relevant contract documents [Article 9 and 11 of the Special Conditions for Construction Contract, Section 11 of the Special Conditions for the site site Terms and Conditions, Section 3-3 of the Special Terms and Conditions for the Special Terms and Conditions for the Construction Contract, as the original type of construction and the additional type of construction work can be evaluated as integrated in its functional aspect, as well as the proposed modification in the construction cost to the extent of cost effort.

In light of the relevant legal principles and records, the above determination by the court below is just, and contrary to the allegations in the grounds of appeal, there were no errors of exceeding the bounds of the principle of free evaluation of evidence against logical and empirical rules, or of misapprehending the legal principles

(b)the additional cost of construction;