Talking with the director of IT for my town. He was talking about how they're moving to service based solutions, and one reason is that finance likes the predictable budgets.
It strikes me that we've never made this argument for OSS. Since you don't pay for versions, and only support in most cases, you'd have even and predictable payments.
Free Software isn't zero cost, but it is consistent and competitive, something finance departments everywhere can understand and love.