I found out the hard way earlier this year that UA codeshare flights on USAir metal do not count toward the 10,000 mile thresholds for earning 4-500 mile upgrades on UA...

I am finding a current cheap SAN-BOS fare on US that includes USAir codeshare flights on UA metal...

If I buy a USAir ticket that is on UA metal via a USAir codeshare on UA, how does UA treat those miles? Same as a standard UA flight since those flights ought to show up on my Mileage Plus account as the UA flight number rather than USAir and since I'll also have to check-in with UA for the flights rather than US..Or would they still get substandard treatment by UA because it's a US Air ticket?

Thanks for any help on this.