The maxi das is a pretty cool unit. We have that, a launch, and a genesis (ugh) at work. Typically the launch is my go to on the BMW. One of these days I plan to play around with the misfire graphing on the maxi, but I haven't yet. Typically when I hook up to the bimmer's they have stored a cylinder specific misfire code.

For kicks you could swap the coil to another cylinder just to see how the graphing responds. Its possible its a plug, or a plug/coil saturated with oil.....

You've got it under control.............

John