Block Time Utilization?

Any ASC managers out there, or any other folks who would happen to know, care to share how you arranged block times for your surgeons, and more than that, how you calculated room utilization rates? I'm managing an ASC that is a department of a large hospital, and leadership uses the same utilization calculations for us as they do for the main campus. But scheduling works differently, and our availability is not the same. I'd like to propose different calculations but I'm not entirely sure what would be appropriate. It would help to have an idea of standards in the industry out there. We are orthopedics but responses from any specialty area would be helpful. Thanks!