(6)In order to provide certainty, both to the Board and to the entities concerned, on how individual annual contributions are to be adjusted in the case of an error in the calculation or changes to the underlying data, this Regulation should lay down specific rules in that respect. Where the Board makes an error in the calculation of the annual contribution, it should be required to rectify that error. Such a requirement should apply as regards errors that occur because the Board applies incorrectly the methodology for calculating the individual annual contributions. In such cases, all contributions should be amended. On the contrary, cases where the input data used in the calculation of individual annual contributions is not correct or is subject to a change after the calculation was performed should not be considered errors in the calculation and should therefore be treated differently. In such cases, only the contributions of the entities whose data was not correct or was subject to a change should be amended.