Originally Posted by Wasabi Tofu

For mileage calculation, ANA uses TPM.
So,
all of KIX-HND,KIX-NRT,ITM-HND,ITM-NRT are same 280 miles defined as OSA-TYO.
As you know, GC uses GC(Great Circle Distance) not TPM.
Anyway, I checked total TPM of your itinerary.

NYC-IST 5002
IST-ADD 2297
ADD-DEL 2830
DEL-BKK 1824
BKK-SGN 453
SGN-TPE 1380
TPE-SEL 914
SEL-OSA 525
TYO-NYC 6723
total 21948