Woah, wait... Layer 5's scrolling properties affect layer 8? That's bad... but it doesn't happen for me

I've had layers 5 and 8 going in opposite directions with no problem, although the layer 5 properties do seem to take over when the game is paused... no choppiness. If it depends on the graphics hardware being used, then it seems like that would only affect hardware mode rendering. Software rendering should look the same on any computer, shouldn't it?

Or maybe it doesn't get choppy if the directions are opposite? I think I'm confused now.