Guess I am trying to understand the difference between the airflow at the tip and the airflow via carb.
The airflow through the tip and the airflow through the air port are two completely different streams and are important for different effects.
Air flowing through the exterior channels of the tip creates the convection portion of the vapor. Air travels under the heated cap, through the tip's channels and through the herb chamber, vaporizing the herb and then flowing into The condenser. The greater the airflow the higher the convection/conduction ratio. More airflow also creates less air restriction without sacrificing vapor production.
When air flows through the air port, the hole in your stem or body, you are introducing fresh cool air which travels between the midsection and condenser until it reaches the tip, where it makes a 180° turn and flows into the condenser. This creates a vacuum and helps pull vapor from the tip as it mixes, cools and dilutes the vapor. This action can be regulated by covering or feathering the air port with your finger.
One controls vapor production and convection/conduction ratio and the other is about Vapor management.