Took the truck to a mechanic's shop that I sometimes use. He's mainly a Mopar & Dodge repair guy, but works on all trucks and cars. Told him what it was doing and the first thing he said was "it's the Blend Door". We went for a ride in the truck to let him check it out. He said mine was very minor compared to what others he had fixed. Told me if it was his truck, he would live with it until it got worse. The amount of air coming thru will barely make a sheet of toilet paper flutter when its placed next to a Dash vent.
If the airflow never increases.......I can live with it.