"[U]sing an estimated rate of return to discount future pension liabilities is not misleading. This discount rate actually reflects the costs of funding pension benefits far better than using a risk-free or low-risk bond rate of return. If appropriately set, the former will reflect an estimate that is much closer to the actual cost of pension benefits and therefore the liabilities of the system. In contrast, discounting these liabilities using a hypothetical bond rate reflects an estimate of the future value of these benefits to plan members. The latter valuation is important: Employers and taxpayers should know the value of pension benefits received by public employees. But estimating this benefit amount does not reflect the actual costs of funding public pensions."