Interpretation of Union law – potential sources of different treatment

“Rather than discussing the ways in which you can or must interpret Union law, I want to make you reflect on the different ways in which such legislation is formulated and thus creates a wider or smaller scope for administrations and national legislators, and may be the source of divergent treatment within the single market.” – with these words, Michael Lux opened the exchange of views on the topic "Interpretation of customs law: the most challenging aspects for business" at the 13th Authors’ Meeting. So which legal formulations lead to different treatments in the EU Member States?