While y'all pay a lot more attention to fare than I do, I suspect that may have more to do with route than anything. If someone else has a reasonably timed one-stop compared to a not-stop, the fare won't be significantly different. But all one-stops aren't created equal. If the one-stop backtracks and thus adds significantly to travel time, it will be significantly less than the non-stop. Hidden city ticketing isn't alive and well for no reason.

Jim