Having recently gone on a bit of a buying spree of cheap 80s compilations to produce a nostalgia-soaked USB stick of MP3s to listen to in the car, I've had the opportunity to listen to the same tracks on different compilation CDs and they definitely do not sound the same. Even on a cursory listen, they sound like someone's been at the faders and EQ during the mastering of the compilation. Some instruments sound louder, some quieter, some keyboard sounds (it was the 80s, after all) sound really quite different and so on. Whether this is caused just by a bit of an EQ tweak by the mastering engineer or something else, I don't know.
Interestingly, the single Ride on Time had two different versions which were not consistently labelled at the time. As this article concludes, '[i]t seems almost to be pot luck which master you get when you licence the track for release':