4. Union entities other than those referred to in paragraph 3 of this Article shall make an annual financial contribution to CERT-EU to cover the services provided by CERT-EU pursuant to that paragraph. The contributions shall be based on orientations given by the IICB and agreed between each Union entity and CERT-EU in service level agreements. The contributions shall represent a fair and proportionate share of the total costs of services provided. They shall be received by the distinct budget line referred to in paragraph 3 of this Article, as internal assigned revenue, as provided for in Article 21(3), point (c), of Regulation (EU, Euratom) 2018/1046.