My wife is currently in the middle of a fight over this. Her salary is paid by a grant from an organization that has a minimum pay scale for postdocs. The university has its own standard pay scale for postdocs, which is about $20k/year lower. So far they've refused to budge. It's not even their money, there's just 4 layers of bureaucracy who have nothing better to do than ~enforce policy~ no matter the cost.