A company pays last monthly salary multiplied by the period of service. The company also allows employees to withdraw 50% of the end of service benefit libility at any time. Example, as of 31/12/2015, an employee has 10 years of service,1000 monthly salary and has withdrawen 5000. Should we calculate the gross benefit based on the projected unit credit method and then deduct the present value of the advance payment OR allow for the advance payment in the calculation of unit cost under the projected unit credit method.