I would note the turbulence factors too.  Could it be that the manufacturer is also looking for a "better mixing" of the fluid (fuel) with the airflow.  It all is smooth, then the mixing too could be streamlined into the crankshaft or up the manifold.  In the case of the crankshaft, it turning could influence the mixing but in a four stroke, if all is smooth, then the point of turbulence would be at the valve opening and that, it would seem to me, to be the least desirable condition.

I think I will stick with the "normal" set up.  I do not need to do such fine tuning.

Chip