One outside air intake for multiple AHUs

Has anyone had experience documenting IEQp1 in the following situation?: I recently visited a facility that has one outdoor air intake for multiple AHUS. A single duct dumps outside air into a mechanical room on each floor. The mechanical rooms have 1-3 AHUS. The mechanical room acts as a mixing box that mixes outside air and return air. Based on the arrangement of units, I am confident that the air is fully mixed. Each air handling unit should receive a proportional amount of outside air. So in cases where there are 2 identical AHUS, each AHU should receive ½ of the outside air delivered into the mechanical room. I could potentially measure the airflow at the outside air supply and divide by 2, but I’m not sure how LEED reviewers would feel about it. The other alternative would be to add additional ductwork that directly ducts outside air to each AHU; however this seems to be an unnecessary expenditure. Has anyone had experience with this situation