These are largely a list of "best practices", yes. Influence and budgetary conflicts between projects and centers can happen from the "shop floor" all the way up to the capital building. NASA's is one of the most earmarked budgets in the federal government, usually shaped by a few key congressmen with centers in their districts. So a budgetary struggle usually ends in some equilibrium between the deemed "core competencies" of a center pitching new work, and the ability of their congressfolk to direct work or facility construction in spite of technical considerations.

(I should probably say that despite the politics involved, I really like what I do. Still the best job I've had by a long shot)