Question was asked just couple of days ago and the answer given was that as far as it is single PNR, original baggage allowance printed ion the ticket will be honored.

For separate tickets, it is sometime cheaper to take along a young relative (or even a domestic help) then pay excess luggage. (for example many times you can get BOM-AMD ticket for about 16 USD. - thats extra 33 pounds of extra baggage allowance at 50 cents a pound.