The way the question was phrased appeared to be seeking special allowances because he was moving from NY/ Washington? because he was earning a lot in that location.
If the question was because he is from the West, that would have been answered differently.
Taking QP as an example (I don't think the situation has changed significantly since I left), there is no difference between the pay scales for Western/Eastern nationals. there IS however a slight difference in the allowances paid i.e WIA.
There IS also a difference in such as school fees. In terms of actual basic salaries paid, each offer is made in line with a statistical trend (using multiple regression analysis based on proven elements) for the appropriate peer group.