(b) in each relevant year beginning on or after 1 April 2021, the revenue  derived by the licensee from the assistance for areas with high distribution  costs scheme activity shall not exceed the assistance for areas with high  distribution costs scheme amount for that relevant year as calculated in  accordance with the following formula:  where  3.  After paragraph 2 insert—  “ 2A.  For the purposes of paragraph 1 above, for the relevant year of the assistance  for areas with high distribution costs scheme beginning on 1 April 2021, the  Shetland assistance amount shall have the value specified in the Energy Act 2004  (Assistance for Areas with High Distribution Costs) Order 2005, and for each  subsequent relevant year the Shetland assistance amount shall be derived from the  following formula:  where  4.  In paragraph 5—  (a) in the definition of “assistance amount”, after “made pursuant to” insert “paragraph  1 of”,  (b) after the definition of “relevant year” insert—  4 HBM$_{t}$  represents the assistance for areas with  high distribution costs scheme amount in  relation to the relevant year t.  A$_{t}$  represents the assistance amount in  relation to the relevant year t.  SA$_{t}$  represents the Shetland assistance  amount in relation to the relevant year t.  HBOC$_{t}$  represents the administration allowance  in relation to the relevant year t.  HBK$_{t}$  represents the correction amount in  relation to the relevant year t.”.  SA$_{t-1}$  represents the Shetland assistance amount in relation to  the relevant year t-1.  RPI$_{t}$  has the meaning given in paragraph 2.”.  ““Shetland  assistance amount”  means the amount payable by the licensee to a relevant  distributor in any relevant year beginning on or after 1  April 2021 made pursuant to paragraph 1A of standard  condition C22 (Assistance for areas with high  distribution costs scheme: payments to a relevant  distributor) and with the value specified in or calculated  in accordance with paragraph 2A above.”. 