3.   In order to simplify administration and to take account of the characteristics of the types of ecological focus area listed in the first subparagraph of paragraph 2, as well as to facilitate their measurement, Member States may, when calculating the total hectares represented by the ecological focus area of the holding, make use of the conversion and/or weighting factors set out in Annex X. If a Member State decides to consider to be ecological focus area the area under point (i) of the first subparagraph of paragraph 2 or any other area that is subject to a weighting of less than 1, the use of the weighting factors set out in Annex X shall be mandatory.