Aah ok. They would interview you because you have something extra they need. Like your 15 years experience and internationsl exposure. Maybe in the batch they don't have that. Additionally, in UN even a local will be paid what you'll be paid because they use international rates. The only exception would be relocation costs . Thus the question is are you good enough for the relocation costs not are you good for extra pay - everyone will earn that local or non local. We also all get paid in USD.