1.1 If at any time after the Payment Commencement Date an Availability Failure or a Performance Failure occurs the Authority will be entitled, subject to paragraphs 1.2 and 1.4 of this Section 3 (Deductions from Monthly Service Payments) and paragraph 1 of Section 4 (Temporary Repairs and Alternative Accommodation), to make Deductions in calculating the Monthly Service Payment in respect of that Availability Failure or Performance Failure, calculated in accordance with this Section 3 (Deductions from Monthly Service Payments) of Schedule Part 14 (Payment Mechanism).
1.2 In calculating the Monthly Service Payment for Contract Month "n", the maximum aggregate of all Deductions that the Authority may make in respect of Contract Month "n-2" is the Gross Monthly Availability Deduction for Contract Month "n-2".
1.3 In any Contract Month where the value of ∑Dn-2 exceeds the value of ASPn/12, the Monthly Service Payment due by the Authority shall be an amount equal to PTC for that Contract Month but the Authority shall, in calculating the Monthly Service Payment in respect of the following and (to the extent necessary) any subsequent Contract Months, be entitled to carry forward and set off the amount of such excess against the amount by which the value of ASPn/12 exceeds the value of ∑Dn-2 (as such values are calculated in the following Contract Month and (to the extent necessary) any subsequent Contract Months) until the amount of such excess has been set-off in full. To the extent that any such excess has not been set off as at the earlier to occur of the Expiry Date and the Termination Date, then an amount equal to such excess shall be immediately due and payable by Project Co to the Authority.
1.4 To the extent that an Availability Failure or a Performance Failure:
1.4.1 is the result of an Excusing Cause; or
1.4.2 [is the result of an External Utility Failure,]
the Authority shall not be entitled to make Deductions.
1.5 To the extent that an Availability Failure or a Performance Failure is the result of:
1.5.1 a Relief Event; or
1.5.2 an event of Force Majeure,
the Authority shall be entitled to make Deductions but any such Deductions shall be disregarded for the purposes of Clause 24.3 and Clause 40.1.8.