I was trying to figure out load for NRT-BKK this weekend, and I found one interesting mileage calculation method. UA9747 & UA9711 which is a NH code share non stop earns 2868 miles. In the meantime, UA837 earns 2887 miles. Now, I'm not really complaining about 19 miles, but I'm curious why the mileage earned between NH code share and UA metal are different. It's not as if UA calculate actual flight path. Anyone have insight as to why this is happening?