Deemed export certification: invoice endorsement and customs verification required to validate claims and ensure proper accountal of supplies. Deemed export supplies to EOUs/STPs/EHTPs/BTPs require invoice endorsement and certification to claim benefits; eligible goods procured under notified procedures are to be verified and certified by Customs/Central Excise, while duty paid or non excisable but eligible supplies must be endorsed by the EOU officer after verification. EOUs must intimate arrival with duplicate invoices within one working day, record and sign detailed account entries, and the Superintendent in charge must ensure a bond officer physically verifies goods within one working day and endorses invoices as proof of supply, with records retained and accountal maintained to address refunds or duty liabilities on subsequent DTA transfers or consumption.