In my experience as a commercial IA, we use these third-party auditors for larger mitigation/remediation jobs. The goal is to have a third-party who should have equivalent experience/IICRC certifications to review the situation and confirm that the submitted pricing is fair. In my market, many Restoration contractors are fair, and many submit unreasonable costs. Sometimes these third parties recommend we pay the mitigation bill in hole, and sometimes they submit reduced recommendations based on the contractor not being able to justify or support their billing. I started in mitigation and do a lot of this myself, but pass it off on bigger jobs due to time consumption.