@Jazibroomi:

But don't you think that would be injustice to the 18th fellow in open merit list? In fact, an injustice to all below the vacated seat. Because the person below the vacated seat has right to the seat vacated, rather than some guy from quota system.

You are right there is injustice but I don't agree with your solution. I think it would be better to allocate to top 17 whatever they want, and then distribute the rest of the allocations. That way merit would be upheld, and nobody would usurp anyone's seats.