What's wrong? I don't see anything wrong with the timings nor the time difference.. everything seem to adds up
And it's normal for flight time to be shorter on one direction than on the other.
Sorry, you are right. It turned out my maths is bad :P. I didn't aware IST is GMT +5:30. (It will be my first visit to any xx:30 timezones countries)
Seems GMT watches have difficulty in handling XX:30 timezones...