what hasn't been mentioned here is the reason for the 2 and 4 stroke cycling, the 4 stroke cycling is so you don't over heat the new engine, causing exessive wear on your piston liner,and other new moving parts, its a gradual process of seating the parts.
when going into the lean run,or 2 cycle operation, your heating the metal and allowing the parts to seat and find its comfort zone when running, this should be done gradually, the reason for the alternating rapid needle valve settings when first running the engine in.

the 4 strokeing allows more oil and fuel into the combustion chamber allowing the engine to run cooler durring the 4stroke cycle,fireing at every other cycle, while still seating the parts like others have pointed out .

OS recomends a rich run for several tanks before leaning your 46AX, I started noticing a slight hesitation with mine after about 8-10 tanks requiring a small amount of leaning of the low end to smooth the transition from idle to full throttle otherwise I never touch the needles at all.

simply put, read the OS manual, if there is a area that doesn't make sense read it again untill you do understand it, there pretty simple to follow,there are many who recomend there own way of breaking in there engines thats good for them but if there is a problem with your engine you can comfortably say you followed the manual to the letter,when you send it in for repair or warentee work.
I have broken in several 2 and 4 stroke OS engines by the manual, there running perfectly every one.