To help you understand your benefits, most of these terms are defined in the Definitions section of your certificate. The Arizona State Retirement System Defined Benefit Plan provides for lifelong monthly retirement income for qualified members.ASRS Defined Benefit Plan. ASRS is a defined benefit 401(a) plan. This provides a guaranteed lifelong pension benefit at retirement. Defined benefit plans provide a fixed, pre-established benefit for employees at retirement. Traditional defined benefit (DB) pensions are experiencing a resurgence as states and cities across the country reinstate and bolster these benefits. Pinnacle Plan Design is a third party administrator (TPA) for employer-sponsored qualified retirement plans, with a physical location in Phoenix, Arizona.