How are miles calculated? Does each airline have their own method of calculation? For example: Flight from Shanghai Pudong to Osaka is 350 miles on ANA but 550 on Air China. We paid full ticket, no discount on both tickets, both are Star Alliance. Price is also almost identical except the time of the flights. I know that if you purchase a discounted tickets you on occasion only get a portion of the miles, if you purchase premium ticket that you get 1.5 or more miles but the actual distance, does it differ by the flight path the different airlines may take?