Under US GAAP, benefits are attributed to service using the projected benefit approach (which typically means ratably over the service period). The guidance does not specifically address attribution when benefits are impacted only for service after a certain age.

The IFRS IC issued an agenda decision regarding the period over which an entity should attribute the benefit for a particular defined benefit arrangement (a lump sum payment when a minimum number of years of consecutive service is provided and a specific retirement age is reached). In that specific fact pattern, benefits should only be attributed to service after the age when service starts impacting either the timing or the amount of the retirement benefits. If consecutive service is not required, then benefits can be attributed from the date of hire.