The “Quarterly 1998 Programme Amount” (‘Q1998PA’) in respect of each Quarter beginning on the BSC 1998 Start Date shall be the amount determined in accordance with the following formula:- Q1998PA = (PACL*r) / (1-(1+r)-L) where: r is the rate (expressed as a quarterly rate, and as a decimal value) determined by the Panel to be the time weighted average of the Base Rates prevailing during the preceding Quarter; L is the remaining part of the 1998 Programme Recovery Period (specified in Quarters) as at the beginning of the relevant Quarter; PACL is the remaining portion of the principal amount comprised in the Aggregate PES Recoverable Amount not recoverable in respect of previous Quarters; has the meaning given to that term in paragraph 1.2.1 of Annex D-5;