All appeals are dismissed.

The costs of appeal are assessed against the plaintiffs.

The grounds of appeal are examined.

1. Regarding ground of appeal No. 1

A. The main sentence of Article 69(2) of the former Enforcement Decree of the Corporate Tax Act (amended by Presidential Decree No. 20720, Feb. 29, 2008; hereinafter “Enforcement Decree”) provides that where the contract period for construction, manufacturing, and other services (including contracting and reservation sales; hereinafter “construction”) is not less than one year, the earnings and losses for each business year from the business year which includes the date of the commencement of construction of the object to the business year which includes the date of its delivery shall be included in the calculation of earnings and losses for the relevant business year based on the construction completion rate as prescribed by the Ordinance of the Ministry of Finance and Economy (hereinafter “work progress rate”), and Article 34(1) of the former Enforcement Rule of the Corporate Tax Act (amended by the Ordinance of the Ministry of Finance and Economy No. 547, Mar. 30, 2007; hereinafter “Enforcement Rule”) shall be included in the calculation of earnings for the relevant business year by the end of the relevant business year by deducting the total construction cost from the total construction amount included in the calculation formula in the business year.

In full view of the legislative intent to prevent the distortion of the profits and losses by allocating profits and losses in line with the language and text of these regulations and the degree of the progress of construction work, “the cumulative total construction cost incurred by the end of the pertinent business year”, which is the divisible in the instant formula, refers to the cumulative total construction cost actually input for the construction of the object by the end