No problem here. I book Song one way and Jetblue the other. For some reason one way is low fare and the other way fare is higher. So I book the lower fare down and the lower fare back. This time Jetblue was $79 down and Song was $69 flying back. Last Oct. it was reversed. Wish I had waited as I could have gotten SW out of Providence for $49 down. But again the flight back would have been higher than I am paying.
I still dont see how R/T is cheaper as I when I price out it is always more than one way on on 2 different airlines.
Just remember which airline to go to for each leg of the trip. Dont go to say Song when you should be a Jetblue.

Although they look me up at the curb to print my boarding pass at both airlines. I have never had to worry about my boarding pass. I just give the guy/girl at the curb my confirmation # and off I go with my boarding pass, less my bags.
So go have a good trip