I think the one point that may help is that when internal auditors do their work, they follow the standards set by the Institute of Internal Auditors. They declare that their reports are in conformity with those standards.
We do ask, in the policy, that internal audit shops subject themselves to a review by the Institute of Internal Auditors to verify their compliance with standards. It's a way of assuring me, or assuring the audit committees, that what the internal auditors are saying about their own performance and conformity to standards is in fact a reliable statement on their part.
So it's not different. It's reinforcing what audit is supposed to be about, which is adherence to standards. The external review is looking at audit itself and confirming that's in place.