1. The Defendant’s each of the Plaintiffs’ KRW 1,200,000 per annum and 20% per annum from March 18, 2015 to September 30, 2015.

1. The parties' assertion

A. The Plaintiffs asserted that they purchased apartment units from the Defendant on October 2014, Seoul Mapo-gu Seoul Mapo-gu 201 Dong, 202 (hereinafter “instant apartment units”). The pre-sale conversion of the instant apartment units should be calculated in accordance with attached Table 1 of Article 3-3 of the former Enforcement Rule of the Rental Housing Act (amended by Ordinance of the Ministry of Construction and Transportation No. 584, Oct. 15, 2007) that was in force at the time of the public announcement of the purchase of the instant apartment units.

According to this, if the mandatory lease period is five years, the pre-sale conversion price shall be the arithmetic mean of the construction cost and the appraised value, but the construction cost shall not exceed the amount calculated by deducting the depreciation costs during the lease period from the price of the relevant house calculated at the time of conversion of rental housing and the housing site cost (hereinafter “calculated price”). The construction cost shall be calculated as the house price interest and depreciation cost at the time of initial recruitment of occupants, and the calculated price shall be calculated as the housing site cost at the time of announcement of the construction cost at the time of initial recruitment of occupants, and the housing site cost shall be calculated as the housing site cost if the State, local governments, and public institutions, such as the Korea Land Corporation and the Korea National Housing Corporation, develop and supply housing sites (hereinafter “public housing site”), and the upper limit price of the construction cost shall be the price publicly notified separately by the Minister

In relation to the apartment site cost of this case, Article 3-3 [Attachment 1] Paragraph (2) of the Enforcement Rule of the Rental Business Act

D. (2) According to subparagraph (a) and Article 18(1) [Attachment 3] of the former Guidelines for Management of Housing Site Development Act, the supply price of rental housing construction sites with a size not exceeding 60 square meters located in the Seoul Metropolitan area shall be 60% of the development cost, and the supply price of rental housing construction sites with a size exceeding 60 square meters but not exceeding 85 square meters shall be 85% of the development cost at each upper limit. Thus, the Defendant is required to discount the housing site cost