Here is my rationale for modifying my 4 strokes to incorporate the breather mod.

In 21 years of repairing OS 4 strokes, I have always found that high time engines with 50 or more hours running time have significant wear on intake valve faces where the valve contacts the seat. In one case the outer circumference of the valve face was completely cut away from the valve which allowed the valve to be swallowed into the intake port. This was on a 120 Surpass engine.

This wear is not found on the exhaust valves due to the hard carbon build up on the valve face protecting the face from wear.

My thought in incorporating the breather mod was to increase the amount of lubrication available to the intake valve to preclude this wear. I do not know if this was also the intention of OS in introducing this breather setup on their latest engines. I do know that their latest engines run beautifully as their carburetors are flowed to adjust for the introduction of air downstream of the carb. Unfortunately I did not have access to their flow bench equipment.