I can confirm this, although I have seen it in other programs on occassion.
I use a microsft wheel mouse, which I have set to accelerate on faster scrolling, the next-to-fastest setting, and I have 1 line per click on normal scrolling. With this setting, I should see normal scrolling when--I don't know, scrolling "normally", I guess, and accelerated scrolling when I. . .you get the picture. Within Mozilla, I get a smooth scrolling under normal speeds, just as in MC. But if I flick the wheel so it spins, this gets the page sailing off at high speed in Mozilla, which is what I want.
However, with MC, if you scroll faster, the page movement does slow down. I saw this a year or two ago in Windows explorer, also. At that time, you could get it to go in reverse, if you scrollied fast enough.
MC acts like its overloading from the scroll input. The funny thing is, playing now is prone to just the kind of wild acceleration when dragging files that we WANT when scrolling. If you could shift the bug from dragging-dropping to wheel scrolling, I think both parties would be happy.
ALSO: I recall Datdude posting on this issue somewhere around v.290. At the time, it didn't seem like a "showstopper", but I know there are a few of us who would like to see this improved.