Hmm... could be.
I think MAME plays all vector games about 3% too fast. It's just a "gut feeling", nothing concrete. I used to play them all religiously when I was a kid. But then again maybe it's just that my reactions have gotten slower.
PS: You had very good score on Gravitar. Respect. Not so many people have skills to master it. It's probably my all time favorite arcade machine.