Prospective operation of Rule 9B(5) proviso preserves refund claims from provisional assessments for earlier periods.

The proviso inserted into Rule 9B(5) on 25.06.1999 applies prospectively and does not bar refund claims arising from finalisation of provisional assessments for periods before that date. Even where the assessment was completed after 25.06.1999, the refund remained outside the doctrine of unjust enrichment because the operative right to refund was tied to the earlier provisional-assessment period. The analysis also distinguishes refunds consequent on provisional assessment from refunds claimed under the general refund provision, treating them differently for unjust enrichment purposes.

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Issues: Whether the doctrine of unjust enrichment could be applied to refund arising from finalisation of provisional assessments for a period prior to 25.06.1999, when the assessments were completed after that date.

Analysis: The dispute concerned provisional assessments relating to an earlier period, but the final assessment and refund-related steps occurred after the insertion of the proviso to Rule 9B(5) by Notification No. 45/99-C.E. (N.T.) dated 25.06.1999. The governing principle, as applied, was that the proviso introduced on 25.06.1999 did not operate retrospectively. Refunds arising from finalisation of provisional assessments for a pre-25.06.1999 period were held to stand outside the bar of unjust enrichment, even if the assessment was finalised later. The decision also relied on the settled distinction between refund consequent upon provisional assessment and refund under the general refund provision.

Conclusion: The doctrine of unjust enrichment was not applicable to the refund in question, and the appeal failed.

Ratio Decidendi: The proviso to Rule 9B(5) of the Central Excise Rules, 1944 applies only prospectively from 25.06.1999 and cannot defeat refund claims arising from finalisation of provisional assessments relating to periods prior to that date.

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