"We switched the project from an hourly rate to a fixed fee after seeing that the costs would be more than we budgeted. This would move some of the risk to Kev

"We switched the project from an hourly rate to a fixed fee after seeing that the costs would be more than we budgeted. This would move some of the risk to Kev and be the right incentive to have him deliver both a working release and the source code." I don't have a lot of experience contracting or being a contractor, but if it's clear that a project is going over budget, what contractor in their right mind would agree to a fixed fee contract? It sounds like that would be a situation with no upside for the contractor. Am I wrong about this?