Right to appeal to Commissioner (Appeals): time-limited filing, condonation discretion, and power to modify assessments. A person disputing an expenditure-tax assessment, liability, or penalty may appeal to the Commissioner (Appeals) in the prescribed form and with any prescribed fee. Appeals must normally be made within thirty days of the notice of demand, though the Commissioner may condone delay for sufficient cause. The Commissioner may hear and determine appeals, including enhancing assessments or penalties provided a reasonable opportunity to show cause is given; where possible appeals should be disposed of within one year and procedure follows income-tax rules.