Consider what Larry Bible has to say in this thread about the knock sensor issue. I agree with him. The gadget is there to thwart off a holed piston, but how long do you want to operate in this mode? The 103 motor in my car calls for 91 octane fuel. Mid-grade has been used & recommended here by some and I am not saying it or lesser grade fuel is inferior, but I personally am not going to try and 2nd guess the findings of MB engineers. I use 93 octane premium. I do realize, as you've stated that this was an unintended incident.

As for the sudden oil loss, I'd fully warm up the engine(15 or more miles of driving), park on a perfectly level surface and let it sit for several hours, then take a dip stick reading. I've seen all sorts of bizarre things happen in this area and have no valid explanation. If your engine would indeed have inhaled that much oil in that distance(seals/guides/rings), your plugs would be
drenched and the cars behavior would have reflected it. I suppose some sort of sudden external leakage could have occurred and I'd think that could be found with visual examination.

Octane requirements?