A key panel of the California Public Employees' Retirement System endorsed a plan Tuesday to reduce wild swings in government contributions, following calls for a pension overhaul by Gov. Arnold Schwarzenegger and other critics. Under the plan, CalPERS would revamp a formula used to calculate annual pension contribution rates for the state, cities and other government agencies. It would also spread investment gains and losses over a 15-year period instead of three years, as it does now. At the same time, trustees agreed to explore legislation to create reserve accounts that government officials can tap to meet their pension payments...