Car parking and increased ventilation

I have a office project with 250 car parking facility, underground and mechanically ventilated. We are going for increased ventilation credit in all spaces. However, based on USGBC's IEQ space matrix and occupied space definition we have excluded car parking from this credit. The parking facility is also CO-constrolled and in action probably would not need that full ventilation more the a few hours in a week. Ofter design application the reviever has, however, taken the side that car parking should be included and is demanding the 30 % increase in ventilation rates. Could you share your opinions, should car parking be included in this IEQ 2 credit ?