OK - So I went back to Discount Tires and instead of them doing Subaru's AWD procedure of crossing tires (front left and back right swapped and ditto), we went left to right front and back, as this and other discussion groups all suggested. And guess what - the problem went away and went maybe slightly the other way - but very very slightly. ANd it was amazing to not have a the pull. So here we are, 18,000 or so miles later, Michelin authorized changing tires with 35% tread gone on "60,000 mile tires" - so I paid 35% plus mounting and it was bitter sweet. But I didn't argue because frankly I still wasn't sure and felt all were doing me a good deed favor. Till I got the the new Primacies on the road. WOW!!!!!!!!!!! These f_---kers are AMAZING!!! I had no idea. Even the steering, which was off for 18 months, is centered again. And utterly peaceful. And dead center stable for the first time! Like all the reviewers screamed about! The Forester feels like a brute in the steering wheel. In other words, all the wonderful things I read about those tires, and never ever experienced since the other set was new, was here - I am speechless - these are fantastic tires and I thought (and didn't mention it in the thread here because I thought my car was just not up to this excellent and responsive behavior) that I have missed out all this time.
And how the bittersweet. I should not have paid a thing! How many times did I go out of lane this last 18 months? Maybe 35% wear was excessive due to the pulling! I paid for two unnecessary alignments!
But now I LOVE how the Forester drives and it is a revelation and the tires really DO make a difference - never really noticed it like this before.
So now I'm going to go to corporate - Discount to get the mounting fees back, and Michelin to challenge the pro-rate they authorized due to all the frustration, wasted time and money, near accidents. Wish me luck!