Is there a minimum period required for joint-use

The school is not in session for 16 weeks of the year and the entire campus and all facilities are with little to no use. Only several security, cleaning staff and administrators are present during this time, but the vast majority of the campus is closed. This will be the case in the current Performing Arts Center that is being added to the campus as well. As such, we are wondering whether allowing joint-use (in line with credit option 1) during the remaining 36 weeks of the year would be sufficient for meeting the intent and requirements of this credit? Hopefully someone has received a related GBCI ruling...