I have given interview in IBM. in that interview they take all details from my side and my expectations was 23-24 which they knows very well. And after getting selected they offer me 16 when I am getting currently 15. It was joke or what I don't know. But was worst experience with IBM i have.

You need to clear written assessment before going to f2f interview round. Interview is mere a formality, if they are looking for a candidate to fill a place, they just go for it, even if you do not fair well