where—

• W is the amount found by the calculation made in accordance with paragraph 6 above;

• X is the aggregate of—

  1. (a)

     amounts paid by the designated authority to the participant authority by virtue of paragraph (1) of regulation 17 in consequence of calculations previously made in accordance with paragraph 6 above; and

  2. (b)

     amounts so paid by virtue of paragraph (5) of that regulation; and

• Y is the aggregate of—

  1. (a)

     amounts paid by the participant authority to the designated authority by virtue of paragraph (1) of regulation 17 in consequence of such calculations; and

  2. (b)

     amounts so paid by virtue of paragraph (5) of that regulation.