Mandatory penalty upheld for duty-evasion scheme involving delayed MRP printing and stock transfers under excise law. The manufacturer removed packaged colour televisions from its factory without printing maximum retail price, printed MRP later at depots, and offered free gifts. Authorities found the delayed MRP affixation intended to evade ad valorem excise duty and held that where the printed retail sale price is the sole consideration the goods attract ad valorem duty after abatement; gifts were incidental and did not alter consideration. The Tribunal and Commissioner treated stock transfers as non-sales, sustained demand under the relevant notification prescribing specific rates where MRP is absent, and imposed a mandatory penalty equal to duty which the court upheld.