I'm playing 1.72.1 on Windows XP 32bit, but I noticed the problem - albeit to a much lesser degree - on Vista Ultimate X64.
The problem seems to be that the number of kills on my data screen increases faster than the actual number of ships I have killed.
When I was playing last night, I had around 260 kills. I left the game sitting overnight as I was about to make the last jump to catch the Constrictor and for some reason I was worried that if I shut the game down, he'd be at some other planet when I loaded it up today. I don't know if his course is randomized, but it seems like it's different every time I play - at any rate, I didn't want to risk it.
Anyway, after I killed him, I docked at the station to find that I now had 546 kills.
Surely killing that guy isn't worth 280 some kills is it? I don't recall that being the case before.
Is it possible that it's counting all deaths occurring in the system, not kills I've actually made and I've been credited for deaths that were going on in the background while I slept???
Like I said, I perceived that my kill number was going up faster than I was actually making kills when I was playing on Vista, but then I never left it overnight before, so maybe it's been crediting me for all the deaths in whatever system I've been in all along.
I feel kinda sad now. My reputation is that I am dangerous, but I'm really probably only slightly above average...

Wouldn't be so bad is I also got the bounty for those deaths too.
Thanks for a reviving a great game and thanks for all the OXPs that bring the things I imagined when played Elite when I was a kid to "life".