Refund limitation for customs duty clarified: computation varies for ad-hoc exemptions, judicial orders, provisional payments, and purchases. Refund applications under Section 27 are subject to a one-year limitation from payment of duty and interest, with alternative computation points where goods are covered by an ad-hoc exemption order, where refund arises from a judicial or appellate order, or where duty was paid provisionally under Section 18 - in which case the period runs from adjustment after final assessment or re-assessment. For non-importers the relevant date is the date of purchase, and payments made under protest are not subject to the one-year limitation.