(60)To ensure consistent harmonisation of rules and supervisory practice on extension of activities and services, colleges and review of models, stress testing and back testing, the Commission should be empowered to adopt regulatory technical standards developed by ESMA with regard to the following: the conditions under which additional services or activities to which a CCP wishes to extend its business are not covered by the initial authorisation; the conditions under which Union currencies are to be considered the most relevant for the purpose of central banks of issue membership in colleges and the details of the practical arrangements for the functioning of colleges; and the conditions under which changes to the models and parameters of CCPs are significant. The Commission should adopt those regulatory technical standards by means of delegated acts pursuant to Article 290 TFEU and in accordance with Articles 10 to 14 of Regulation (EU) No 1095/2010.