Valuing Real Property in 401k

[Guest halka]

Plan owns non-employer real estate as investment. Realtors typically charge a 10% commission to sell such property. Should/may/must the trustee reduce the annual property appraisal by some amount to reflect anticipated selling expenses?? Or should trustee simply ask the appraiser to address expense of sale in appraisal? Would answers change if/when trustee makes decision to sell or actually lists property w/ realtor? Any regs or experiences greatly appreciated.