I am guessing this is going to be a utilization schedule. What would it look like?

For reference, ASHRAE 90.1 - 2010 Appendix G3.1.1 exception (d) - For kitchens with a total exhaust hood airflow rate greater than 5000 cfm, use system type 5 or 7 with a demand ventilation system on 75% of the exhaust air. The system shall reduce exhaust and replacement air system airflow rates by 50% for one half of the kitchen occupied hours in the baseline design. If the proposed design uses demand ventilaiton the same airflow rate schedule shall be used. 

Please let me know, how you would approach this problem.

Thank you.