Well I for one think that the remaster is simply just the original tapes recorded onto a new medium at a higher bit depth and resolution and not a rerecording,this is obviously a get out clause for copyrights with dreyfus and by rendering certain tracks(Most notiably Part 4 ) slightly different mix wise,like for instance there is a delay on one of the "Fssh" sound towards the end of the song which is so obvious it was meant to be delayed to make it sound different from the orginal,as well as the missing Phaser Mod on the MP7,which would suggest Jarre did all those during Mixdown on the original,so obviously still has an archive of those individual tracks as he's used them for Live performances in the Past and plus the Glock sound,the 2 notes in the intro wind section,has a high amount of background noise,which if rerecorded in such high definition audio Quality Jarre would have been able to eliminate that or at the least notice it?you cna hear it even at Low listening levels.
To me that suggests that the tracks were taken from the original tapes for this mix,any clean rerecording wouldn't contain that Noise,when its pretty much non Audiable in the original,because it wasn't recorded onto analog machines an the frequencies would have been saturated so that it wouldn't be noticable on lower rate playback,hence why its now noticable in this newer Version.
Jarre couldn't record that exact a second time some 30 years later,the VCS FX in Part 2 are impossible to replicate like the original,if you understand the EMS synth make up Jarre himself has even admitted in the past he couldn't replicate them exact as they were played by hand almost intuitiavly,so howcome some years later they are the same,infact the same as the ones he used for AERO Versions too,A little funny seeing as he said he wouldn't be able to replicate most of them and he can't do it for these Live perfromances neither,infact the sound he Triggers is so far removed from it.!!!!!!
the majority of Oxygene Album was played by hand,so if that was such the case that he could rerecord it exactly this time for this remaster then the live Performances we have seen would be more closer to the originals,which they are not for at least 75%,they are only sound wise in some cases...He can't even play half of the tracks parts live correctly,so why would it be exact for a rerecording,he'd either have to have some technically good players or have everything Midi'ed up for replication so close,given the Instruments Doubt it so much...Its simply a souped up original version.
I just don't buy it as a rerecording,call me Fickle,pedantic or whatever. or I can say the old well I'm a musician so I know Bullshit line,No I'm not Jarre's righthand man neither so How could I be sure line too,Anyone who beleives its a rerecording Remaster simply hasn't listened to the orignal Oxygene close enough.its simply not a rerecording.Jarre may have revisited the Mixing side of it,but he certainly didn't play it all again
It pretty obvious its all about the Copyrights,that he has to make it seem like it was rerecorded,when its plain to Hear it wasn't..
I also got hold of a promo CD with Oxygene 4 that will arive shortly 
because I reread your post and you wrote "practically." 
it the same when I first heard it. One of my favourite tracks from the album. 
) of playback (?)...