So I am back at it. I setup up an 18" X 18" test area on a flat wall to make it easier to quickly see the difference in performance in the center, mid point and outer corner.
In order from best to worst:
Rustoleum flat white "High Heat" 7751 (10% TiO², 5% Talc) (satiny/flat, slightly off white to the eye, easy to get a smooth finish)
Color Place flat white 259865 (5% TiO²) (satiny/flat, slightly off white to the eye)
Rustoleum flat white 7790 (15% TiO², 15% Talc) (very flat, very white, rough texture)
Rustoleum aluminum "Metallic Finish" 7715 (10% Aluminum flake) ( PITA to get a smooth finish)
Rustoleum semi gloss white 239108 (15% TiO², 10% Talc) ( PITA to get a smooth finish)
Rustoleum gloss white 7792830 (15% TiO², 5% BaSO⁴) (visibly white) ( PITA to get a smooth finish)
So although the the 15% flat white is truly flat, like chunks of eggshell. It diffuses the light too much. The flat white heat paint is more like a satin. Same with the Walmart color place flat white, it is satiny smooth. I tracked down the MSDS, turns out it is made by Rustoleum and it has 5% TiO². It also significantly outperforms the 15% TiO² flat white.
So that raises the question, why did the 10% TiO² flat white heat paint outperform the 15%TiO² semi-gloss white? I think it was because the semi gloss has extra resin added.