I don't understand the physics of the Vortex, but then, there's much physics I don't understand
Same as I don't get the temp diff between my Maverick and the Tel Tru. I get the same diff on my 18" WSM. I have a Tel Tru mounted in a similar location to the Kettle, just off the top of cooking grate. And the Tel Tru always reads about 20* lower than the Maverick. Sometimes I wonder if heat from the cooking grate does not transfer to the Maverick temp sensor ??? IDK.
But I will continue to use my Vortex to indirect cook wings. On top of the temp diff, it was easier to use than the charcoal baskets.