Article 16 — Requests for investigative measures in relation to national rules

1. Where a Member State has set short notice periods shorter than 30 days for specific sectors on the basis of Article 3(1), point (b), of Directive (EU) 2019/633 and another Member State has done the same, resulting in short notice periods of equal length for the same specific sectors, the enforcement authorities of those Member States may agree to make use of the possibilities provided for in Article 8(1) of this Regulation. Similarly, where a Member State has maintained or adopted stricter national rules, on the basis of Article 9(1) of Directive (EU) 2019/633, and another Member State has done the same, resulting in equally strict national rules for the same size of operators or the same types of unfair trading practices, the enforcement authorities of those Member States may agree to make use of the possibilities provided for in Article 8(1) of this Regulation. 2. Where an applicant enforcement authority makes use of one or both of the options referred to in paragraph 1, the requested enforcement authority may refuse to take investigative measures, without indicating the reasons for that refusal. In such cases, Article 13 shall not apply.