Welcome to the Cove!
We have an often used response here in the Cove when we encounter situations like this:
"Show me the 'shall'!"
This simply means you are not required to accept any finding from a customer's auditor or a third party auditor unless they can cite chapter and verse in a document you agree applies to your operation which proves the assertion of nonconformity.
There is absolutely no comment anywhere in ISO 9001:2000 nor TS16949 nor AS9100 which addresses the issue of stamping or signing any documents. The only possible alternate documents which can contain a procedure you don't conform to in this instance are
- Contract between you and customer
- Your own written procedures or work instructions.
I doubt the contract from your customer would be so specific, so the only remaining option is your own procedure. There is a possibility you have adopted a procedure from another organization which does not exactly fit your operation. If this is the case, you may accept the finding of nonconformance and formally change your procedures to eliminate this requirement which does not seem to apply to your operation. Thus you will have implemented a Corrective Action which should satisfy all parties.
Moral:
If an organization adopts a Procedure, it must abide by that Procedure or be nonconforming to its own rules. It is necessary, therefore, to look carefully at all your Procedures (the purpose of an internal audit) and see whether or not the members of the organization follow those procedures.
If the procedures are not followed, two courses of action are available:
- require employees to follow procedures
- modify the procedures to something which makes sense and which employees can follow.