As per case facts, Hindustan Petroleum Corporation Limited exported Light Diesel Oil, Furnace Oil, and Aviation Turbine Fuel as ship's stores for foreign-bound vessels. They contended that these goods, supplied ... from bonded stock, should be exempt from excise duty under Rule 13 of the Central Excise Rules, allowing export under bond without immediate payment. However, excise authorities demanded duty, which HPCL paid under protest, subsequently claiming refunds. These claims were rejected, and although some appeals were initially allowed, they were later set aside by the Tribunal, following a Delhi High Court judgment. HPCL then filed civil appeals before the Supreme Court. The question arose whether the appellant was liable to pay excise duty under Rule 13 (export under bond) or Rule 12 (rebate on duty paid) for excisable goods exported as ship's stores. Finally, the Supreme Court ruled that Rules 12 and 13 are complementary, not independent. Rule 13 provides for deferred payment under bond, but the final excise duty liability is determined by Rule 12 and its associated notifications. The Court rejected the view that Rule 13 granted total exemption, as this would lead to discriminatory results and violate Article 14. Thus, the appeals were dismissed.