As a data point, I flew PVG-LAX-ATL on 9/7/15 as an AA Platinum (thus OW Sapphire) in J with a 4 hour layover at LAX. The counter person initially denied me access based on the fact that the lounge was accessible only on *departing* and *international* OW flights. I fussed and they "made a one time exception." But I'm pretty sure that my itinerary qualified.