Just thinking outloud.. especially after following 3mp's M1 experiment and seeing how the frequent replenishment affected the numbers, if my engine burns 1L of oil every 3,000km, I should be able to extend the interval to maybe 12-15K km since during that time I will have added 4-5L of fresh oil? Or maybe change the oil filter at 10,000km and extend the interval to 20,000km which would mean about 7L of top up oil? What do you guys think of this idea?