Hmm, just wondering if the smaller venturi is why it's atomizing the fuel better. May be wide of the mark, but if it has the same size opening on the filter side, and a smaller one on the engine side the airflow would speed up, higher flow would tend to blow the fuel mixture better.
Kinda like the difference of using a garden hose, same pressure going into it, but if you squeeze the end instead of the water just running out, it sprays out at a higher velocity. But what do I know...