2. When assessing the consistency of performance targets for en route air navigation services with the Union-wide performance targets, the Commission shall take due account of local circumstances and interdependencies between key performance areas referred to in Article 21(3), point (a).
The Commission may allow a deviation of performance targets for en route air navigation services from Union-wide performance targets with respect to a key performance area where deemed necessary and proportionate to ensure consistency of performance targets for those services with the Union-wide performance targets with respect to other key performance areas.