State how the benefit to be attributed for the employee service for the last 20 years, 10 and 20 years and within 10 years, be measured.

As per Ind AS 19, the benefit will be attributed till the period the employee service will lead to no material amount of benefits. And service in later years will lead to a materially higher level of benefit than in earlier years. Therefore, for employees expected to leave after twenty or more years, the entity would attribute benefit on a straight-line basis. Service beyond twenty years will lead to no material amount of further benefits. Therefore, the benefit attributed to each of the first twenty years is 2% (i.e. 40% divided by 20) of the present value of the expected medical costs. For employees expected to leave between ten and twenty years, the benefit attributed to each of the first ten years is 1.5% (15 % divided by 10) of the present value of the expected medical costs. For these employees, no benefit is attributed to service between the end of the tenth year and the estimated date of leaving. For employees expected to leave within ten years, no benefit is attributed.