IPS statement for Defined Benefit - return objective

Can someone tell me other than 1) actuarial rate, 2) capital gains focus/ income focus depending on liquidity need, what other elements should be indicated on the return objective of defined benefit plans? One of the scheweser questions (one about Ellington Food pension) cites an observation of fund being overfunded as part of return objective and I don’t see how that is part of return objective. Any thoughts?

Overfunding > Surplus > Ability to take risk increases > Warrants a higher return objective