In my completely uninformed imagination, I see the OneWorld organization having one or two staffers with the part-time responsibility of maintaining an "official" star file for OWE, trying their best with limited resources to quell inter-airline quarrels about how to map the rules onto reality. Meanwhile, the airlines are left to their own to interpret the existing rules.

We've all found plenty of times when different rtw/rate desks give significantly different answers to the same question. If Cathay thinks it's trans-pacific and that works to anyone's advantage, they should conspire to ticket with Cathay. If trans-atlantic works better, float some trial requests with the other carriers until you get the right answer. Then stop asking, grab the tickets, and enjoy the trip. The AAgent who check you in for ORD-DEL will be totally clueless about what direction you're going or should be going next.