Where -
(a) an energy company includes a letter of expression of doubt with a return for corporation tax purposes in accordance with section 959P of the Act of 1997, and
(b) by reason of the amendment of an assessment referred to in subsection (5) of that section there is -
(i) an increase in the taxable profits in a chargeable period, or
(ii) a decrease in the average taxable profits in respect of the reference years,
then any additional temporary solidarity contribution that is due under an amended assessment, following the amendment referred to in paragraph (b), shall be due and payable in accordance with section 959AU(2) of the Act of 1997, as applied by section 10.