I have a trip to Asia coming up this summer. Since United sometimes runs a DEQM promo during the summer months, I'd like to position myself to earn those if it comes up. The trip is 3 segments. Flying all segments on UA is currently ~$950 more than flying CO. The thing is, the first two segments of the CO booking is actually the exact same UA flights as the UA booking (the flights are operated by United for CO). The 3rd segment (~200 miles) is the only difference: it would be on a UA partner if I fly UA, on a CO partner if I fly CO.

Scenario 1: If I book the trip on the cheaper CO ticket with my UA MP# listed and DEQM is announced, would I still earn DEQM for the two CO segments operated by United?

Scenario 2: Another alternative involves booking a United ticket on Asiana codeshare flights.

Of course, it's almost certainly too early to purchase right now, so the price difference may narrow. But we're lately being forced to fly based on price alone, so I'm not always able to specify UA.

Thanks!
TBH