khn, if it is paid by the plan, the plan is the client and the amount of the expense would come within the ambit of the plan administrator's fiduciary responsibility. If it is paid by the plan sponsor, not the plan, then depending on the subject of the advice or other legal service, it may still be for the plan, but in such a case only the quality of the service, not its cost, would be a fiduciary responsibility. Because of the lack of transparency regarding legal fees and, arguably, comparability, it will be very difficult to benchmark. I think most sponsors pay plan-related legal fees as an employer expense partly for this reason.