I shadowed at multiple locations, and the AA was at the hospital at 6am as surgeries start as 7. they finished when the surgeries were done for the day. some days they were the lucky one and got to leave 12-1. most days they left about 2. on the long days they got stuck with the late cases and were there til 3-4. It evens out in the end.
I can imagine if it is outpatient, and you only work 7-12, 5 days a week, you would get paid commensurately, even if salaried.