The judgment below

Among the plaintiffs B, C, D, E, F, and G loss parts, the part against the other plaintiffs is reversed, and this part is reversed.

The grounds of appeal are examined.

1. The reasoning of the lower judgment on basic facts and the record reveal the following facts.

On December 31, 2011, the Plaintiffs, who are the Defendant’s employees, received retirement allowances calculated according to the interim settlement of accounts between the Defendant and the retirement allowances.

In calculating retirement allowances, the Defendant calculated part of the annual bonuses among family allowances and special bonuses that the Defendant paid every month (hereinafter “instant bonuses”) without including them as average wages.

The Defendant’s benefit provision provides that “The amount calculated by dividing the average wage by the total number of days during which the allowances paid in three months in the calendar from the day before the day when the cause for calculation occurred and all other money and valuables paid in the name of the calendar shall be included” (Article 3). The Defendant’s benefit provision provides that the average wage, which serves as the basis for the calculation of the retirement allowance, shall include the amount calculated by dividing the bonus paid within one year, counting from the retirement day by 12 (Article 26), and that the allowances for family allowances shall be included in the allowances

(Article 17). The Defendant’s benefit provision originally applied the progressive system in the calculation of retirement allowances, but the Defendant and the Defendant’s trade union agreed on the conversion of the fractional system after January 1, 2010 and the progressive rate as of December 31, 2009 and revised the benefit provision.

2. Family allowances and whether the instant bonus is the average wage that is the basis for the calculation of retirement allowances (the Defendant’s ground of appeal) is based on the interpretation of the wage rules that include bonus, etc. in the calculation of retirement allowances at any workplace. It shall be interpreted by comprehensively taking into account various circumstances such as the payment practices at the workplace and the process and contents of the amendment of the wage regulations.

(2) The Defendant’s bonus and family allowance are the same as the Defendant’s bonus and family allowance, in full view of the content of the Defendant’s wage provision and the details of the payment of the instant bonus and family allowance along with the aforementioned legal doctrine.