Man I loved this game. This'll be fun to work with.

Oh, okay. Yeah, perhaps this could be the result of the OST spacial placement (front and back speakers on different levels) while the organ is distributed to all of the channel pairs (Great division = front, Positive division = back, Récit = surround, Pedals = LFE/C with bass split). This configuration may cause some amplification or cancelling effects, which in my case did cooperate and worked to my advantage.

Nope, quite the opposite. Your surround mix (or your surround recording) appears to be better in clarity and staging for some reason. Or let's say the clarity is almost the same - but the panorama and staging catches my attention much more.

Thanks @Master Mi, much appreciated! This "difference in clarity and staging" -- do you, by coincidence, mean that the stereo mix appears to be somewhat "cleaner"? Sorry if I didn't quite get it. 😕

Not sure if it's just the source material, your good mixing skills or the recording of your nice room impression. But with my Beyerdynamic DT 880 Pro studio headphones, I can really hear a noticeable difference in clarity and staging between the original stereo mix: ... and your surround mix: Whatever you really did to the original mix - good job, dude. ))