Call and book different fare classes?
 

Is it possible to call in and try to book an M fare for the outbound and the cheapest fare class available on the return flight? Will the agent be able to do this for me? Thanks.

Deleted. Noticed you want to mix.

But this probably doesn't solve the OP's problem, since one can only select the minimum fare class for both the outbound and inbound on nwa.com. Meaning, if you select "Coach Class M (or higher)" from the dropdown to get a M class on the outbound, res.nwa.com won't give you a cheaper fare class on the return, which is what the OP wants (without having to book two one-ways, I assume).

Yup, I wanted to mix and get an M fare outbound so I can use the one-way Plat upgrades on the outbound but maybe pay less on the return because I've noticed that there are cheaper fare classes on the flight I am trying to book.

I'm just wondering if anybody has done this before. Thanks.

I have done it through a travel agent but not directly with NW. I don't see why it couldn't be done through NW though. Just figure on their $20 phone fee, probably what a travel agent service fee would be. But I would be surprised if NW wouldn't book this for you.

Note the direct booking fee is waved for Gold and higher.

Ok cool, just wanted to see if anybody has done it. I'll make the call thanks!

Its totally possible and happens all the time...The easy thing about calling is that we can ck the pu503 upg avail at the same time and process it all at once....Very easy to find the lowest combineable fare etc and then even get the Exit row if avail on the low fare return....If you gotta sit in coach, then go for the Exit!!