Current Service Cost and expected return on plan assets

CFA Level II FRA
#1

Can someone please explain the following:

  1. Current Service Cost is computed by discounting the benefit payments post retirement after one year of service to the period in question. Why is it so? Benefit payments will increase as the number of years of service increases. For example, if an employee has 25 years of service left, the current service cost n the 3rd year is calculated using the discounted vaue of benefit payments calculated using one year of service. Similarly if I were to calculate the cuurent service cost of the 20th year i would have to ue the same benefit payments to find out the present value. only the number of yeas(n) to caluculate wull change.Why do we use the benefit payments derived after one year of service the compute service cost for any year?

  2. How is expected rate of return on plan assets used for financial reporting?