Bikeguy Joe I don't at all have a hard time believing in some hard running during break in. The worst thing you can do is hold it wide open constantly followed by the close 2nd going constantly any other speed. You want to run it through its range varying the load regularly. I think I get and agree w/ what your saying about the 10 min. You want to start it up and run it for 10 min or so making sure to warm it up to operating temp running it through the rpms a bit w/o steadying at any speed and w/o over reving ( and not under load). That will get the rings started seating to the crosshatch in the cylinder.
But heres the skinny. I think that Ol' MC is right I think that synthetic is too viscous to allow the necessary abrasive action of ring seating. In 4 strokes wouldn't blow-by taint your oil at the very least causing it to go acidic? And much the same in 2 strokes? That in addition to lower compression. Don't Know fo sho about the synth but I know that petro works. So possibly the negitive results not necessarily noticed but perhaps subtly percieved.