I just booked a r/t through the CO Elite Desk 800# for me, my wife and and our 2 small kids. The outbound flight is operated by UA and the return flight is by CO. For the return flight, the CO person put all 4 of us in the CO "plus" seating based on my Silver status. For the outbound, since it is a UA flight, the CO person did not have access to UA's seat map and told me to call UA directly.

UA is telling me only me and 1 companion can get E+ seats now, not all 4 of us as per CO rules, and to ask at the airport for upgrade on day of flight.

I thought the CO and UA rules have merged so that I was treated the same regardless of which status and which plane. Who's right here?