I dont think that is a good argument. In chemical engineering world, the provider who just randomly changes formulations would be called "ureliable, shoody, crappy giving us something we not ordered".
It’s not random. You’re setting up a straw man of what such a change would be. You can arrive at the same chemical formulation through different means. You may also need to tweak a formulation to achieve a variant effect, ie increased resilience of decay from uv light or countless other reasons for tweaks that would necessitate a construction change. It’s the construction I used as the analogous engineering component of this, and that is where an engineer designing the production system would need to understand the changes that the formulation (comparative item to formulation in this metaphor being the model and its underlying components, chemicals, methods of arriving at the end product).
Changing the production or operating process in the face of changing inputs or desired outputs is the bread and butter of countless engineers.