4. Member States may, subject to the approval of the Commission, revise one or several performance targets, during a reference period where alert thresholds are reached, or where it is demonstrated that the initial data, assumptions and rationales underpinning the performance targets are to a significant and lasting extent no longer accurate due to circumstances that were unforeseeable at the time of the adoption of the performance plan. The Commission shall approve this revision if it concludes that the revision is necessary and proportionate and the revised performance targets are consistent with Union-wide performance targets.
In such a case, Member States shall revise the performance plans with respect to the targets concerned, in accordance with the procedures set out in Articles 23 and 24. The consultation referred to in Article 23(8) may be limited, for the purpose of this paragraph, to the performance targets and parts of the performance plans which are directly or indirectly affected by the revision.