Huh? Why do you think this? The implication seems to be that they want to pocket the rest or something?

Let’s not forget, we are talking about NASA here, not a private corporation. Why would an arm of the federal government have any interest in not doing “anything beyond the exact specific minimums of the grant”?

I cannot speak to building rockets, but I do know about other types of government financing, and I can tell you that the scientists and engineers who would have received such a grant, would have no reason not to use as much of it as possible. In fact, that’s exactly how they would justify a need for more in the future.