To answer first question in two parts Part 1 - I do not wait till I hit the reserve light be it my car or bike. I have a habit of refueling after covering 200-300 kms at best. I know people who will tell me I will be carrying dead weight and reducing mileage, but to me this method has served me well, especially when I plan to drive out the car unexpectedly. Part 2 - All numbers that are posted here are tankful to tankful methods only, just that the distance covered varies as to where I am refueling. On the second question, I post these mileage values to document the FE under various conditions, thats the reason the distance, fuel consumed, average speed and where it was refueled from is also noted. Another reason for the shorter distances is due to the quality of fuel available in the city and the places elsewhere I generally travel. It has turned out better to fuel at known stations than unknown ones. This has contributed to refilling at a particular station rather than the distance already driven from the previous refuel. Hope this answers your query.