Supplementary show cause notices must remain within the original...

Supplementary show cause notices must remain within the original notice's scope, comply with limitation, and allow an adequate opportunity to respond; fresh grounds introduced through late corrigenda breach natural justice. Preferential customs exemption based on certificates of origin cannot be denied without reliable evidence of inauthenticity, particularly where certificates were verified at import and remain uncancelled. Reclassification of decorative stainless-steel wall panels and profiles requires Revenue to discharge its evidentiary burden through representative samples, technical evidence, and legally admissible statements. Transaction value cannot be rejected or enhanced without compliance with valuation procedures and evidence of additional consideration. Where misdeclaration and undervaluation fail, suppression with intent to evade duty and related penalties do not survive.