As used in this subpart--
Discount for prompt payment means an invoice payment reduction offered by the contractor for payment prior to the due date.
Mixed invoice means an invoice that contains items with different payment due dates.
Payment date means the date on which a check for payment is dated or, for an electronic funds transfer (EFT), the settlement date.
Settlement date, as it applies to electronic funds transfer, means the date on which an electronic funds transfer payment is credited to the contractor's financial institution.