Not the same thing....VAT and duty are different taxes, both applied to fuel purchase.
Duty should be charged on private, pleasure flying only - according to the EU rules. In the UK they charge nobody duty on jet fuel and expect the pleasure flyers to 'fess up and send a cheque. In other countries they charge everyone regardless but most operate on an AOC only basis. This is contrary to the EU law.............The IOM issue commercial use certificates because AOC flights are not allowed on their register.
Perhaps we should lobby other aviation authorities to do the same for commercial companies and/or aerial work outfits?
VAT is charged unless you are VAT-exempt due to being international and AOC. Except by the countries who do reverse charging for VAT registered companies.......VAT paid on that basis can (should be able to) be reclaimed through the VAT system.