Value addition duty mechanism: prescribed percentage rates and refund or credit procedures for eligible manufacturers in specified northeastern States. The amendment substitutes the preamble and replaces paragraphs in Notification No.20/2007 to impose a duty payable on value addition for eligible goods manufactured in specified northeastern States, prescribing percentage rates by tariff chapter and capping the duty by the duty actually paid other than by CENVAT. It establishes monthly filing and refund procedures, permits manufacturers to take the refund amount as account-current credit (subject to conditions and verification), and provides a process for applying for and fixing a special rate representing actual value addition, including calculation rules and provisional refund provisions.