I did some digging around on the 79 release Japanese H1 soundtrack LP and found some interesting info about it’s origins on why the takes are different.
In the past I had read they were alternate takes by Carpenter given to the pressing company. I talked to a reliable musician who had worked in the industry in Japan who stated they were re-recordings by famous Japanese synth wizard Osamu Shoji done on a Roland System 700. The actual soundtrack on the film was in mono and the proper stereo mix done by Alan Howarth was released later in 83.
These Japanese pressings read “Spacesizer 360 System Recording”. It’s basically a 4 channel mix to give the listener somewhat of a surround sound experience. These were meant to be played on a good stereo system. I’m assuming since the stereo mixes were unobtainable at the time, the Japanese company went their way on making their own mix.
