The requirements set out in paragraph 1 of this Article shall apply to the entire pool of exposures backing the securitisation. Subject to Article 252, the originatorinstitution shall calculate risk-weighted exposure amounts with respect to all tranches in the securitisation in accordance with this Section, including the positions in relation to which the institution is able to recognise credit risk mitigation in accordance with Article 249. The risk weight to be applied to positions which benefit from credit risk mitigation may be amended in accordance with Chapter 4.