I think that oil that promotes better wearing-in is probably mineral oil, as opposed to ashless dispersant oil. I'm no petroleum expert but the way it was explained to me by Lycoming is that ashless dispersant keeps particles in suspension(which you don't want while the engine is breaking in, I suppose?) while mineral oil deposits it as sludge and stays at the bottom of the pan.

All I know is my first Mercedes (a 190E) wasn't properly broken in and I had oil drips, a rough engine and generally a dissapointment for a MB. After that lesson, all others after that were generally trouble-free and DRY.

So, I AM holding back the throttle on this one as well