Systematicity and objectivity (Kant, transcendental principles)

Despite the usual commentary on his position, Kant's goal is not to "found" Newtonian mechanics, but to provide a realist interpretation of it. In other words, he tries to show how the laws of this mechanics must apply to the objects of our experience. In my view, these laws give us the conditions of the application of the transcendental Principles. But eventually Kant has to add a principle of simplicity to these other Principles in order to guarantee the unity of the whole set of the objects of our experience, an addition that does not go very well together with other elements of the Transcendental Philosophy.