I am almost sure this is because the system would have to pass a certification procedure somewhere, and for that they would need this level of clarity. Am I right?
Some companies have process and development practices down pat: things go smoothly, and meeting the qualification process objectives is easy, because the work has been done right the whole way.
Other companies have less established or less consistent process. They generally meet the process objectives and deliver a working product, but the development process is often more of a struggle, and there is often a lot of "cleaning up" of missed pieces at the end of the release process.
This is just to say: companies and products in the safety critical space don't necessarily have some intrinsic quality, just a higher minimum bar.
I wouldn't assume that.