4. Companies shall not diverge from the default values for the well-to-tank emission factors set out in Annex II to this Regulation for fossil fuels. Without prejudice to paragraph 1, companies shall be entitled to diverge from the default values for the well-to-tank emission factors set out in Annex II to this Regulation provided that actual values are certified under a scheme that is recognised by the Commission. That certification shall be done, for biofuels, biogas, RFNBO and recycled carbon fuels, in accordance with Article 30(5) and (6) of Directive (EU) 2018/2001 or, where applicable, in accordance with the relevant provisions of Union legal acts concerning the internal markets in renewable and natural gases and in hydrogen.