Starliner is the capsule, SLS is the rocket. SLS [1] is not a fixed price contract. The government's dumped tens of billions on it already, and continues to throw good money after bad. And the "fixed" price contract for Starliner keeps getting adjusted with NASA giving them hundreds of millions more dollars, allowing them to skip certain qualifying tests, and so on.
[1] - https://en.wikipedia.org/wiki/Space_Launch_System