To make an analogy, we have a incredibly well thought out and progressive Constitution in the US. That document has served us well for over 200 years. But every day the Legislative Power keeps on plugging and so does the Judicial system. Judges interpret the constitutionality of an issue on a daily basis. It is part of the "game". Since the ISO 9001 Standard was deliberately written to apply to as many as possible business environments as possible, BECAUSE of that, it does require common sense application and interpretation. If it were not for that, the TC 176 would have not developed an official for a for deliberating and posting “official/sanctioned” ISO 9001:2000 interpretations.
In my opinion, what 3rd party auditors MUST NOT do is to limit the range of acceptable interpretations to their "comfort zone". Typically, there are many different ways to comply with any requirement of a management system standard. 3rd party auditors should verify that the organization being audited has found a meaningful, sound, way to comply with the requirement for their business system. Unfortunately, poorly qualified auditors allow their baggage to interfere with the concept of a fair assessment and try to “impose” their way to system being audited. That is WRONG.
And just to exemplify how requirements NEED to be interpreted, I will borrow a requirement from AS9100, in relation to the control of scrap material:
Product dispositioned for scrap shall be conspicuously and permanently marked, or positively controlled, until physically rendered unusable.
What constitutes a conspicuous and permanent way of identifying scrap material? A red tag? Some would say that a tag is not permanent. Spray the product with red ink? Some would argue that ink is not permanent. I have seen a number of very experienced aerospace auditors arguing over ways of complying with this requirement. So the point is: there will be different interpretations over any requirement, but as long as the organization implementing the system has defined a solid way of demonstrating that they have addressed the requirement, they should not be concerned with auditor’s “opinions”.
One more point. In my opinion, if an organization disagrees with an interpretation from a 3rd party auditor, the complaint process should NOT be the first line of action. Accredited registrars must have an APPEAL process which by, registrants can argue against what they believe is a bad judgment call by the auditor. And there is an escalation process for the appeal process. Still in my opinion, a complaint should be used for systemic problems, not isolated disagreements.
And, even though I don’t have hard numbers/data, my estimate is that, for the registrar that I work for, we have some kind of appeal about an auditor’s interpretation in about 2% of the audits we perform. And from the appeals process, my estimate is that 50% of the time the nonconformities are overruled. We are continuously trying to “calibrate” our auditors, but until human cloning is commercially viable, we will have to live (and manage) with the fact that auditors do have differing views, sometimes. It is inherent to the process.