Indiana Code Title 5. State and Local Administration § 5-10.2-8-4

Sec. 4. A plan established under this chapter exists and serves in addition to other retirement, pension, and benefit systems established by a political subdivision and may not result in a reduction of any retirement, pension, or other benefit provided by applicable law.  Any compensation deferred under the plan shall continue to be included as regular compensation for the purpose of computing the retirement and pension benefits earned by an employee.