My understanding from one of the articles was that McDonalds wanted them to make a special model that did away with some portion of the manual process in favor of press-button maintenance, and they did.
Unfortunately, it turns out that it's hard to replicate the reliability and adaptability of human manual labor mechanically sometimes.
The point is that McD-corp gets IceC-corp big money by mandating a single machine from them. IceM(achine)-corp do this through broken maintenance process. Hence IceM-corp see machines very often and ensures as a third party that food-safety of ice-cream produced by these machines is satisfied. This is what McD-corp is getting back from it. They don't trust die Franchises and let them pay money for their own inspection.