Randy, in your experience, are QMS audit times normally determined solely based on IAF MD 5 Annex A Table QMS 1 or are there frequently adjustments made based on risk, complexity, system maturity, repetitive processes, etc.?
Yes to all of the above (basically). I've had to increase as well as reduce based upon the inputs and information I have. One catch for multi-sites is the same basic risk applies (Low-Medium-High), but depending on the amount of MS areas that are the sole responsibility of the HQ/central location up to an additional 20% reduction can be factored (subject to approved justification of course).
A hazard mentioned by Sidney is "low balling durations" by CB's. From my perspective, because I work as a contract auditor with a specific day rate for audit delivery alterations to duration could be suspect, especially increases (I'd make more money), but as a practice, before I recommend and increase, I have the recommendation reviewed and have had the work assigned to someone else the next time...But that's me and it's only happened a couple times. When I recommend a reduction I just go ahead and do it, continuing to march (I've nothing to personally gain and there's a low COI potential).
Duration's are touchy, you need to have adequate time for a good/effective audit while at the same time doing what's right/ethical for all parties involved.