Alright, here goes...
Awk is talking about increasing timing by shaving the head. The spark plug sparks in relation to crankshaft position so unless you change the stator plate (do a timing mod) the spark plug will spark at the same time each time. But, you have to remember what the crankshaft is doing while it's also telling the ignition system when to spark, it's moving that piston (or face as you made the analogy) upwards as well.
Now imagine the face analogy, if you're getting punched in the face and you're worried about timing.... don't you think changing the position of the puncher would have an affect on the punchee? Lowering the spark plug by shaving the head by 2mm on an engine with 57mm of stroke is like advancing the timing 1.5 degrees (or something like that) even without touching the timing plate...
Also, the reason timing has less of an effect on the top speed or top end of a 2 stroke is because of the maximum volumetric efficiency of the top end with a given expansion chamber.
2 strokes are naturally self limiting because the efficiency of the cylinder drops dramatically as you get out of the tuned range of the head pipe.
If you were only worried about power at top end, you'd order a drag pipe with specs tuned to 10,500 RPM and run +6-10 degress of timing advance. Then the timing advance would work at those high RPM's.
Also, the CDI box on the blaster has it's own timing advance which moving the timing plate may have an adverse affect on which cannot be characterized so easily. The CDI box might be dead on the money as far as advance goes above 4K rpm but be a little "off-tuned" at lower RPM's. Moving the timing plate forward 4 degrees gets the timing right where the stock timing is wrong but it actually over-advances at the upper RPM's making the timing not "optimized" at the upper RPM range. I don't know for sure, but it's definitely a possiblity.
