I agree with all of the above.
I have over a hundred customers including defense contractors, automotive, earth moving, aerospace, ships, Department of Defense and Navy, and others. Once, I even welded a few parts for the vehicle that was driven on Mars.
I deal with many codes and military standards. I'm audited a half a dozen times per year. Government audits are the toughest.
I prepare all welding documents myself. I send out samples for tension testing and NDT as required. AWS Accredited Testing Facility has never been an issue. Most customers want to see my welding system and how I accomplish their audit points.
I might make a hundred different parts for a customer, but they usually only need to see a few (aluminum, stainless, steel, with each process) full-blown PQR's.
I think that AWS ATF’s might be overkill.
Good Luck,
Keith