Regulation 20 Consequences of change in contract categorisationI1

redetermine the amount of any charges for energy supplied under the contract prior to the date of such revision on the basis of the discounted supply price applicable to the contract as re-categorised;

determine the amount by which any such charges already included in any invoice or statement of account are to be revised to reflect such redetermination;

notify the customer of its determinations under paragraphs (a) and (b) and take the necessary steps to ensure the amount in paragraph (b) is credited or debited to the customer by way of credit note, or adjustment of an existing invoice or statement of account, or inclusion in a future invoice or statement of account.