I know this is an old thread, but I got the price change message at the last minute while paying for a multi-city booking this morning on aa.com and just wanted to rant about it. I'm going from SBA-BOS, and I put a reservation on hold last night for $285 out the door. Then this morning I decided to plug in Boston by way of Miami for the extra 2k miles, and I got a fare of $360 out the door, which is slightly less per mile. I set it up as a multi-city:

Day 1
trip 1: SBA-MIA
trip 2: MIA-BOS

Day 2
trip 3: BOS-MIA
trip 4: MIA-SBA

This isn't a mileage run, btw...I just figured as long as I'm getting in a plane anyhoo, I might as well rack up as many miles as possible (especially if it's less cost per mile!).

I went and canceled my hold for the $280 fare and started paying for the $360 multi-city, but when I clicked to submit my credit card info it jacked up the fare on me to $460. I tried logging out, changing from Firefox to IE, but nothing worked.

After reading this thread, I decided to try Orbitz and ended up having no problem setting it up as a $360 mutli-city there.

Kind of annoying and silly if you ask me...I still got the fare. The only difference is that AA probably lost a bit of $$ by my going through Orbitz.