That makes sense. Why cannibalize sales of the full greatest hits when most fans already have 18 of the 19 songs (the 19th being "Together")? If the iTunes version has "Together" as an "album only" track (i.e. you can't download it individually—you have to purchase the full album) that would make even more sense.
At any rate, there will be as-yet-unnamed remixes of "Together" as well as an extended version. I would like to interject here that, thank god, Pet Shop Boys have been offering extended versions of most of their singles since 2003, and as a fan that's been fantastic. I still play the one for "Miracles"—perhaps their greatest single of the '00s (and thankfully included on Ultimate)—quite often.
Also included: a cover of The Dave Clark Five's 1963 hit "Glad All Over" (#1 UK, #6 U.S.), which has apparently become a bit of a football victory anthem in Chris Lowe's hometown of Blackpool. This is also produced by Tim Powell (formerly of Xenomania).
When I think back to 1991, I think of a couple things, musically: becoming obsessed with the local oldies radio station, and bands like Jackson 5, Frankie Valli & The Four Seasons, the Four Tops etc. (What is it with numbers?) Not so much The Dave Clark Five, but this song was always played quite generously. It's also the year Pet Shop Boys released their first greatest hits, Discography. So in my small world, this is kind of a full circle thing.
The other "new" song in the "Together" package (which includes two CD singles and a digital bundle) will be a cover of "I Cried For Us."
Says the PSBs' official site:
"Neil sang this song by the late Kate McGarrigle, mother of Rufus Wainwright, at her memorial concert at the Royal Festival Hall in London in June in an arrangement by Pet Shop Boys. Chris and Neil produced this studio version which was mixed by Pete Gleadall."Here's the liver performance mentioned above:
Overall, "Together" seems like it's going to be a nice little stocking stuffer.