Common use of Invoices for amounts Clause in Contracts

Invoices for amounts. not described in Sub-Sections 1 and 2 above, which may become payable hereunder by the Purchaser, shall be submitted after applicable costs have been incurred or such other time as may be specified in this Contract. Such invoices shall be payable at a reasonable bank rate of exchange (to be agreed to by the Parties) applicable at the time such costs were paid by the Contractor, and shall be accompanied by a certificate of the Contractor explaining such amount and certifying that it is payable.