@Future Ninja
Coincidentally, I studied the Internal Auditor section today, and had a very similar question.
As CPAexcel explained it, contingencies and valuation are HIGHLY JUDGEMENT BASED. As the external auditor, the audit report must reflect your judgement. You cannot rely on the judgement of an Internal Auditor, although in some circumstances you can use their work, or supervisor work they perform for you).
On the other hand, the existence of fixed asset additions is not very subjective. Either the fixed assets are there, or they are not. It would be easier to verify that work performed by an internal auditor.
Remember, the point is that as the external auditor, the client is relying on your judgement, not that of an internal auditor. The buck stops with you (in the report). If an error is later found, and a valuation is off by a large percent, you can't go back and day “but that is what the internal auditor thought was correct”
Does that make sense?
FAR - [10/07/2013 --> 66] [07/07/2014 --> 86]
BEC - [08/31/2014 --> 86]
AUD - [11/24/2014 --> 88]
REG - [02/14/2015 --> 92]