Yeah, what FewMiles said. They're not an exact mirror due to the different carriers. I was going to mention that; it was on the tip of my typing fingers as I entered my last message, but I figured that the routing was the overriding factor in determining if a ticket was circle trip and that the carrier is irrelevant.

So then.

I am now convinced that the answer is "All of the Above." And that's my final answer, Regis!