I'd like that as well, but I don't believe that every point has a study associated with it. I am going purely on deductive reasoning and logic.
I did mention the relative risk of anesthesia complications, not the absolute risk. It doesn't matter how safe anesthesia gets.
If you are liable for 4 rooms instead of 1, your risk of adverse events is going to be much higher than if running a solo room.
I cant speak for every MD practice or every ACT practice, but from my anecdotal experience, I have seen better quality of care delivered at MD only practices.