Is mileage for the STAR RTW tickets calculated based on point-to-point mileage, or on the actual route flown ? For example, if I am travelling from JNB to MAA, it would be on SQ, doing JNB-SIN-MAA. Is the mileage calculated JNB-MAA, or JNB-SIN + SIN-MAA ? This will make the difference between STAR1 and STAR2 for the itinerary as it currently stands, so I'm extreemely curious!

thanks !