Typically, incurred cost audits and audits of interim requests for payment (i.e. voucher reviews) are performed by the contract auditor (DCAA or Defense Contract Audit Agency for DoD contracts) and reports are sent to the contracting officer for resolution if there are any findings noted.
New Regulation Formalizes Ombudsman Practice and Identity for IDIQ Contracts
An ‘ombudsman’ is an official charged with addressing and/or investigating the interests of individuals’ or companies’