1. When defining the relevant tiers for fuel streams, to determine the scope factor, each regulated entity shall apply the highest tier as defined in Annex IIa.

However, the regulated entity may apply a tier one level lower than required in accordance with the first subparagraph where it shows to the satisfaction of the competent authority that the tier required in accordance with the first subparagraph is technically not feasible, incurs unreasonable costs, or that methods listed in Article 75l(2), points (a) to (d), are not available.

If the second subparagraph is not applicable, the regulated entity may apply a tier two levels lower than required in accordance with the first subparagraph, with a minimum of tier 1, where it shows to the satisfaction of the competent authority that the tier required in accordance with the first subparagraph is technically not feasible, incurs unreasonable costs, or that, based on a simplified uncertainty assessment, the methods set out in lower tiers lead to a more accurate determination of whether the fuel is used for combustion in sectors covered by Annex III to Directive 2003/87/EC.