[URGENT] Sec 11AC Penalty imposed A Clarification

Hello Sir. This is the fact of a case study. After a search in the factory of Mr XYZ, some documents and clandestine goods were seized. Now the excise duty has come to , say 10 Lac. Now the penalty has been imposed as per Sec 11 AC at 100% of the Duty. But if it paid within 30 days of the said period, the penalty is reduced to 25% of the duty. The Show Cause Notice has been issued by DGCEI who calculated the duty. Now the case has been forwarded to Additional Commissioner for levy of penalty, interest and personal penalty along with release of the seized goods. The Addl Com after going through the matter will pass a Demand Notice for final payment of Duty along with interest and other charges. Now my question is , which date one must consider for calculating 25% penalty, the date of Show Cause Notice by DGCEi, or Demand Notice by Additional Commissioner? Help would be highly appreciated.