1. The plaintiff's claim is dismissed.

2. The costs of lawsuit shall be borne by the Plaintiff.

1. Basic facts

A. The Plaintiff is a company mainly conducting safety inspections, precise safety diagnosis, the structure design of public structures, etc., and the Defendant is a company mainly conducting the construction plan and design business.

B. In 2015, the Defendant and the comprehensive architect C concluded a service contract by setting forth the contract amount of KRW 78,00,000 for the structural structure among the construction works of the Plaintiff and the D Apartment Construction, as well as KRW 15,60,000 for the contract date, KRW 15,60,000 for the completion of the construction deliberation, KRW 19,50,000 for the completion of the construction project approval, KRW 23,400,000 for the supply of the shop design, and KRW 3,90,000 for the completion of the use approval.

(hereinafter “instant service contract”). C.

The Defendant paid KRW 23,400,000 to the Plaintiff on May 23, 2016, and KRW 19,500,000 on June 19, 2016.

[Ground of recognition] Facts without dispute, Gap evidence 1, 2-2 and 3, the purport of the whole pleadings

2. The assertion and judgment

A. The Plaintiff’s assertion completed the structural calculation in accordance with the instant service contract and completed the supply to the Defendant on June 2016.

After that, the executor, the contractor, the defendant, and the plaintiff entered into the second design modification contract for the structural change of the design for the DNA apartment construction work, and paid 60,000,000 won, which are 80% of the structural calculation cost of the instant service contract (the first), as the second design cost.

The Plaintiff completed the work following the second design change and issued a tax invoice, but the Defendant paid only part of the amount of KRW 70,200,000 to the Plaintiff.

Therefore, the Defendant should additionally pay to the Plaintiff KRW 27,300,000, and KRW 60,000,000, in total, as a result of the second design change structural calculation, for the service payment under the instant service contract.

B. In full view of the following circumstances, the above facts of recognition, evidence Nos. 4 to 54, and evidence Nos. 1 to 54 (including paper numbers), and evidence Nos. 1 to 5 (including paper numbers), and witness E’s testimony, the evidence alone presented by the Plaintiff and the Defendant.