Retrospective amendment to packing machine rules enables refunds of excise collected and removes retroactive penal exposure. Amendment enacts a retrospective amendment to rule 8 of the Pan Masala Packing Machines Rules treating the rule as amended from an earlier date, deems the Central Government to have had retrospective rule making power, and mandates refunds of excise duty collected that would not have been collectible had the amended rule been in force, subject to the statutory refund framework, while prescribing an abbreviated limitation period for refund claims and removing penal liability for conduct retrospectively rendered non punishable.