I flew the DC-10 for a UK operator (Laker) many years ago and the fuel load was very much left to the discretion of the crew but it was explained, in training, that every time you took an extra 10 tonnes of fuel it took 1 tonne of extra fuel to get it there.
I then went to a Part 121 operator at JFK and that company policy was to take Plog fuel unless there was a huge reason to do otherwise.
Initially, I viewed this idea as akin to catching leprosy but I got to like it. It took all the guesswork out of the equation. When you bowled up over Long Island and the man said "take up the hold at Mickey intersection at F250" then it was very easy to say that I do not have such fuel so "organise a divert to Bradley please".
This took ALL of the guesswork out of the equation and saved you going round in circles for ages whilst pursuing a lost cause.