(Not disagreeing with you or questioning you - trying to learn here.)
So how does that work? I mean what's the chemistry that makes it work? Soot comes from carbon and there's the same amount of carbon in the tank before and after you add the additive barring minor dilution. Soot also depends on burn parameters, EGR etc and the truck keeps adjusting these all the time anyway.
Speaking generally, I'm sure some automotive fuel additives really do work, but I'm equally sure others are snake oil. So it seems the only reliable way to tell them apart is a combination of understanding the chemistry, and independent direct comparison like-for-like experimental lab tests (not, with the greatest respect to the experience of this forum, subjective anecdotal non-experimental field tests without proper like-for-like control samples). This will no doubt offend some passionate defenders of additive X, but no offense is intended. I'm just trying to understand HOW an additive reduces soot.