If:
(a) a final VOLWARE price or an interim VOLWARE price for stabilized crude petroleum oil or condensate (as the case requires) has been, or is taken to have been, determined under the Petroleum Excise (Prices) Act 1987 for a month and an oil producing region; and
(b) that oil producing region is constituted by or includes:
(i) a particular prescribed production area within the meaning of section 6B; or
(ii) a particular prescribed new production area within the meaning of section 6C; or
(iii) a particular prescribed condensate production area within the meaning of section 6CA; or
(iv) a particular prescribed intermediate production area within the meaning of section 6D;
that determination is taken to have effect, and, at all material times to have had effect, in the application of that section in respect of stabilized crude petroleum or condensate (as the case requires) obtained from that production area, as if it were also a determination of that price made in respect of that particular production area.