Here's the deal.
Remember that Billy Joel was under contract to Family Productions for 10 albums, the horrible contract he signed with Artie Ripp (or something like that). When the 1st album he put out an Family tanked (Cold Spring Harbor), mostly because it was pressed with the master tape running fast, Billy was pissed. Along the way, he did the live concert on FM Radio that got the tune "Captain Jack" played on FM radio all over the East Coast and got him noticed. Columbia was interested and wanted to sign him but he had that horrible contract with Family. Walter Yetnikoff went to Family and made a deal. Part of the deal was that the LP's would come out on Columbia with a Family logo on the Columbia label, and the tapes would come out on Family exclusively. Thus, the 8 tracks, cassettes and Q8's were released on Family, which used Ampex, and the LPs came out on Columbia. Eventually, Walter Yetnikoff went to Family and made them a forceful offer to buy out the original Billy Joel contract. He then handed the rights back to Billy, as a gift!! What a guy!
This is also why 'Turnstiles' never came out on Q8. By then, Family Productions was pretty much moot.
The Q8 is far more discrete than the SQ, even decoded with the best decoders or scripts. It's almost "too discrete", as it hits you over the head with directionality. The orchestra on the grand tunes is isolated in the rears, and blasts out of silence when the time is right. It's quite a listen.