“What is a perfect audit ?"
ISO compliance is verified by audits performed by the registrar's professional auditors.
These professional auditors verify the compliance of the system to the requirements of the standard as well as the system implementation.
Typical audits, result in a few nonconformances being identified.
Occasionally, there is only one nonconformance identified
Rarely, there are zero nonconformances identified!
This is only possible when the system reflects the organization perfectly and it completely satisfies every requirement of the standard!