June 28, 2017 17:54 Updated Follow There are several things that factor into the final cost of extra service. We suggest you read Buying Extra Service Credit if you are a member of PERF or TRF. For other funds, . Related articles I was in the military. How can I add this service to my account? When will I be vested in PERF? What is service credit? How much can I contribute to my PERF account? How do I contact INPRS?