June 30, 2017 16:35 Updated Follow If you buy service credit, that added service will increase your monthly pension benefit amount. Read more here. Related articles What does service credit have to do with my monthly pension benefit? Can I buy extra service credit in PERF? What is my Defined Contribution account? Am I allowed to make voluntary contributions to my PERF plan? What if I don’t know my username and password to log on to my PERF or TRF account?