737incognito, welcome to JAR!
You are right, there are some unclear paragraphs within the entire set of JAR.
It's good to know, but don't think too much about it, it wont help. Keep in mind that the final authority in regards to how much fuel is taken remains with the commander of a flight. Dispatch can't decide and even the nominated post holder flight operation can't.
So as long as you have a valid reason to take more fuel than plannend take it if you as the commander decide that it will be neccesary for the safe operation of the flight. As long as you don't take extra fuel, becuase you always take 500 kg more for grandma, I doubt that someone would say anything. If so confront them with the regulations.