my opinion of additives is as follows:
You do not need an additive to diesel with low sulfur content . diesel is mineral oil and lubricated enough.
Biodiesel has less energy, but carries oxygen , so when burned in the engine burns more completely , but not enough to meet the diesel and do fewer miles per tank.
cetane additives are different . better and some worse .
gain of 11% I think so .
I am using a cetane additive when I miss a mixture of gasoline more recycled vegetable oil , sunflower , rapeseed and olive oil.
I tried to take the same additive when my car runs on diesel, the idle goes from 800-900 rpm , the car note with more power and disappears completely black smoke.
additive I use is this :
Using Vegetable oil as a diesel fuel - vegi-boost
with 0.1 % is very noticeable .