Special audit can be ordered to verify declared value and input credit, potentially triggering assessment action for discrepancies. A special audit can be ordered by an officer not below Deputy Commissioner with Commissioner's prior approval when declared value or input tax credit appears incorrect or abnormal; a Commissioner nominated chartered or cost accountant must submit a signed audit report within ninety days, extendable once for ninety days. The audit regime applies despite other audits, requires that the registered person be heard before audit-derived material is used in proceedings, and mandates that the Commissioner determine and pay the auditor's expenses. Detection of unpaid, short paid, erroneously refunded tax or wrongly availed/ utilised input tax credit may lead the proper officer to initiate assessment or recovery action.