The contractor (or leader in the case of a joint tender) must send an invoice for payment  of the balance within 60 days of the end of the period of provision of the services, as  provided for in Article I.6, in the tender specifications or in the specific contract. Payment of the invoice and approval of documents does not imply recognition of the  regularity, authenticity, completeness and correctness of the declarations and information  they contain. Payment of the balance may take the form of recovery. The contracting authority may suspend the payment periods specified in Article I.6 at any  time by  notifying  the contractor (or leader in the case of a joint tender) that its invoice  cannot be processed. The reasons the contracting authority may cite for not being able to  process an invoice are:  Suspension takes effect on the date the contracting authority sends the  notification . The  remaining payment period resumes from the date on which the requested information or  revised documents are received or the necessary further verification, including on-the-spot  checks, is carried out. Where the suspension period exceeds two months, the contractor  (or leader in the case of a joint tender) may request the contracting authority to justify the  continued suspension. Where the payment periods have been suspended following rejection of a document  referred to in the first paragraph of this Article and the new document produced is also  rejected, the contracting authority reserves the right to terminate the specific contract in  accordance with Article II.18.1(c) . On expiry of the payment periods specified in Article I.6, the contractor (or leader in the  case of a joint tender) is entitled to interest on late payment at the rate applied by the  European Central Bank for its main refinancing operations in euros (the reference rate)  plus eight points. The reference rate is the rate in force, as published in the C series of the  Official Journal of the European Union,  on the first day of the month in which the payment  period ends.  Suspension of the payment period as provided for in Article II.21.7 is not considered as  giving rise to late payment. Interest on late payment covers the period running from the day following the due date  for payment up to and including the date of payment as defined in Article II.21.1.  However, when the calculated interest is EUR 200 or less, it must be paid to the contractor  (or leader in the case of a joint tender) only if it requests it within two months of receiving  late payment.  41  II.21.8. Interest on late payment  The contracting authority must  notify  the contractor (or leader in the case of joint tender)  as soon as possible of any such suspension, giving the reasons for it.  II.21.7. Suspension of the time allowed for payment  Contract number: ECHA/2020/666  (a) because it does not comply with the FWC; (b) because the contractor has not produced the appropriate documents or  deliverables; or (c) because the contracting authority has observations on the documents or  deliverables submitted with the invoice.