OK, I might be on to something here. My music voice commands have been completely broken since the update and as I said in other posts, I have a gut feeling the old info was never truly wiped out during the update process and a new index was writing over residual info from the old index and confusing the system. Idea popped into my head Saturday night. Leapt out of my chair and bolted for the driveway (the rather abrupt nature of this scared the hell out of my wife as we were just sitting there calmly and quitely watching TV). Anyhow, ran out to the car, pulled the iPod and Nav card and started a Master Reset.
While the reset was taking place I went back in, grabbed an old jump drive, wiped it out and reformatted it. I then threw two of my son's albums (by one artist) on there. Music that has never been on my iPod or in my car on either version of MFT. It took about 10-12 seconds to index/build voice commands (28 songs on two albums by one artist so I didn't really expect it take that long). After it was done, I yanked the drive and performed another Master Reset. Upon completion of the second reset I put my iPod back in. The good sign was that it significantly longer to index/build voice commands (about twice as long as it took after the update).
When it was done, I sat out there for about half an hour giving it "Play Song" voice commands. Still getting choices in a lot of cases but the difference was that instead of my usual screen after screen of four songs that made no sense, it more often than not gave me only two choices, one being the song I said, and even the other one I could see how the system could make think it sounded like the one I said instead of the page after page of nonsense I used to get, none of which sound even close. Even more encouraging was the fact that after a while I would go back to songs I first started telling it to play and it would nail them first time even though 15-20 minutes earlier it was giving a choice of two.
So....anyone having problems with their music voice commands after the update here is something to try. While still not quite as accurate as it was for me on V2.11 it is much much better. Of course, like all things MFT I want to observe it over time but so far, so good. I'm supposed to drop it off tomorrow for a caliper replacement and a new APIM. Don't know if I need the new APIM now or if I should just let them do it.