The extra fuel will be being burned in order to regenerate the Diesel Particulate Filter that your style of driving will not. You need to keep a very close eye on the oil sump dipstick. If you see the oil level rising, this is neat diesel that has been introduced to the engine to burn off the particulates but has instead sunk into the sump, contaminating the lube oil there and raising its level. If this rises beyond the danger level, the compression ignition engine will start running on its sump oil and could become uncontrollable and blow up.