Robertson said 22,500 government employees are eligible to retire today and changing payments would cause an exodus, particularly among workers who are eligible to retire but are years away from being 65.
"It would decimate the workforce today, particularly the institutional knowledge," she said.
The cost-of-living adjustment is typically referred to as a "13th check" because many retirees take it as a lump payment at the end of each calendar year. However, they have the option to receive the cost-of-living adjustment each month.
Fillingane said PERS took a financial hit when the stock market dropped during the Great Recession but its financial standing is improving as the economy recovers.