Same, with me too this diwali, had booked 3 tkts from sdah, and later on changed boarding from Dhn. Pantry boy refused for dinner, then I spoke to TTE, he also refused by saying this is rule, when I asked him what about my money(600/-) which I'd paid for the food, he had no answer, So guys best way is this opt out food option while booking in this condition(boarding change)