Interest on delayed refunds applies when a refund is unpaid past the statutory period, accruing until payment is made. Section 56 provides that if a refund ordered under section 54(5) is not paid within sixty days of receipt of the refund application, interest at a notified rate not exceeding six per cent accrues from the day after the sixty-day period until payment; where the refund follows a final order of an adjudicating, appellate authority, tribunal or court, a higher notified maximum rate not exceeding nine per cent applies for the same accrual period, and appellate or judicial orders against a proper officer's order under section 54(5) are deemed to be orders under that sub-section.