Determination of tax: procedural rules on stays, hearings, demand limits, interest and recovery, and no double penalty. Procedural safeguards for tax determination exclude periods of judicial or tribunal stays from limitation computations; where fraud-based notices are found unsustainable, authorities shall proceed under regular notice provisions. Appellate directions must be implemented within two years. A written opportunity of hearing must be granted when requested or when adverse decisions are contemplated, with limited adjournments for sufficient cause and reasons recorded. Orders must state facts and basis; demands cannot exceed notice grounds or amounts. Interest on tax shortfall is payable regardless of its mention in orders. Unpaid self-assessed tax and interest are recoverable under recovery provisions, and penalties under these provisions bar duplicate penalties for the same act.