Commissioner's revision power: call records and revise subordinate orders, subject to appeal bars, fee and time limits. The Commissioner may call for records of proceedings decided by subordinate authorities and, on his own motion or on application by the assessee (subject to fee and time conditions), inquire and pass orders not prejudicial to the assessee. Where an Assessing Officer's order is found erroneous and prejudicial to revenue, the Commissioner may, after hearing the assessee and making inquiries, enhance, modify, cancel or direct a fresh assessment, subject to statutory limitation periods and exclusions for rehearing time and stays.