Hello, I'm a new AS MVPG (after my first year of serious travel) and I like it so much I want to make sure I qualify next year, too. So this is my first post, pardon if it's an obvious question.

I'm flying SFO-DCA for work, and getting the cheapest ticket is supposed to be our priority, but if a couple of tickets are in the same price range, I can go with one that suits me. I found an itenerary that was great on NW, but it was $434. However, I found the exact same flights on a CO codeshare for $238, and that's one of the cheapest prices I can find, period.

Two questions:

1.) This is one of those cases where it's the metal that matters, yes? Since NW miles qualify towards MVP status, and the plane is NW, it doesn't matter that I book it as CO?

2.) I have some MVPG upgrade coupons good on NW. Can I use these even if it's booked through CO? Will I be able to call day-of-flight, or will I have to wait until I get to the airport?

Thanks so much for any advice, I really appreciate it, this board is a great resource. In case the flight numbers would be useful, they are:

Feb 2nd
12:35 pm Depart San Francisco (SFO)
Continental 5428 / 6822
Connect in Detroit (DTW)

Feb 15th
11:40 am Depart Washington DC (DCA)
Continental 5315 / 5369
Connect in Minneapolis (Minneapolis-St. Paul Intl.)

Thank you!