well the other factor is that quantity always matter, on some patrol pumps, the digital meter shows the amount u asked for, but the person who fills the patrol put something in the mouth of pipe which stops the flow of patrol but the meter doesnt stop, so in 10 litter price u get 7 and u pay for 10, and 3 litr price is the person pocket, after all he pays the manager only the patrol that is used from main tank, extra amount in his pocket,
Akhar hun nay be tu kuch kamana ha, bahi idher sab kuch ho sakta ha ..