Maybe this was true but
Rules 3rd edition page 5
These (nine (9) OEMs: BMW Group, Chrysler LLC, Daimler AG, Fiat Group Automobiles, Ford Motor Company, General Motors Corporation, PSA Peugeot Citroen, Renault and Volkswagen AG ) are the subscribing members and auditors have to give precedence to their products.
Just because other companies use different methods dos not change the facts.
The Big 3 CSR's are in fact remarkably lacking in the actual requirements from the suppliers, and only regurgitate the standard without actually documenting real requirements that are in other documents. They remind me of Quality Manuals of some companies that just have to say it all again!