(2)Regulation (EU) No 575/2013 differentiates between material extensions or changes to the Internal Ratings Based Approach (IRB approach) and Advanced Measurement Approach (AMA) that are subject to approval, and all other changes that are subject to notification. As to the latter there is no indication in Regulation (EU) No 575/2013 on the timing of notification of the extension or change, i.e. whether the change should be notified before or after its implementation. It should be considered that extensions or changes of minor importance need not be known to the competent authorities in advance. Further, it would also be more efficient and less burdensome for institutions to collect such changes of minor importance and notify them to the competent authorities in regular intervals. Indeed, this has already been supervisory practice in several Member States. Thus, extensions and changes requiring notification should be further split into extensions and changes requiring notification before their implementation and extensions and changes only requiring notification after their implementation. This would further ensure that competent authorities in their daily tasks focus their attention on extensions and changes with the potential of materially altering own funds requirements or the performance of the models or rating systems. It would also ensure that institutions distinguish between extensions and changes of great significance from extensions and changes of minor importance on the basis of a risk-oriented supervisory approach. Such a distinction between extensions and changes subject to notification before implementation and extensions and changes subject to notification after implementation, would be prudent, given that the notification before implementation would provide the competent authorities with the possibility to review the correct application of this Regulation. This in return would also reduce the supervisory burden on the institutions' side.