in
theory a QS decode and an SQ decode of the exact same content of the exact same mix should not sound wildly different from one another when run through a Surround Master, if the mix has a guitar prominent in the Rear Right channel both SQ and QS decodes should plonk it mostly in the Rear Right.
however, where it might get a bit messy, is if you check out the Rears only of each decode, whereupon i'm pretty sure you'd find the SM wiped out leaked CF content back there better on the QS decode than on the decoded Rears of the SQ encode. its something i've gone on about before, SM QS decodes obliterate CF content from the Rears whereas SM SQ decodes don't.
one day i'll get that Quadrafile LP set and give it a go...
tbh i'm surprised AOQ or someone of that ilk hasn't done tests of the Quadrafile set thru the SM already to see how it handles the same stuff in QS and SQ.. they probably have and i'm just out of the loop, he did a great job on his SM shootout after all