Dear Friends,
Discount not known at the time of removal of goods forms part of Assessable Value and accordingly duty is to be paid on removal. (Exception is Provisional assessment). Any discount given after removal are eligible for any refund of duties until and unless unjust enrichment is evidenced.
In the recent case, party has adjusted CENVAT Credit and if discount is allowed afterwards and the same is mentioned on the credit note without reference to the duty involved therein, then NO CENVAT REVERSAL required.
Discounts subsequent to removal can be price discount or Reduction in price don't qualify for CENVAT reversal.
Further in GST Regime, Debit Notes / Credit Notes are statutory document and the principle of unjust enrichment therein also has to be prooved to claim back refund from Excise Department.