Application and calculation. Agencies will use the following procedures in calculating interest due on late payments:

Interest will be calculated from the day after the payment due date through the payment date at the interest rate in effect on the day after the payment due date;

Adjustments will be made for errors in calculating interest;

For up to one year, interest penalties remaining unpaid at the end of any 30 day period will be added to the principal and subsequent interest penalties will accrue on that amount until paid;

When an interest penalty is owed and not paid, interest will accrue on the unpaid amount until paid, except as described in paragraph (a)(5) of this section;

Interest penalties under the Prompt Payment Act will not continue to accrue:

After the filing of a claim for such penalties under the Contract Disputes Act of 1978 (41 U.S.C. 601 et seq.); or

For more than one year;

When an agency takes a discount after the discount date, interest will be paid on the amount of the discount taken. Interest will be calculated for the period beginning the day after the specified discount date through the date of payment of the discount erroneously taken;

Interest penalties of less than one dollar need not be paid;

If the banking information supplied by the vendor is incorrect, interest under this regulation will not accrue until seven days after such correct information is received (provided that the vendor has been given notice of the incorrect banking information within seven days after the agency is notified that the information is incorrect);

Interest calculations are to be based on a 360 day year; and

The applicable interest rate may be obtained by calling the Department of Treasury's Financial Management Service (FMS) Prompt Payment help line at 1-800-266-9667.

Payment. Agencies will meet the following requirements in paying interest penalties:

Interest may be paid only after acceptance has occurred; when title passes to the government in a fast payment contract when title passing to the government constitutes acceptance for purposes of determining when interest may be paid; or when the payment is an interim payment under a cost-reimbursement service contract;

Late payment interest penalties shall be paid without regard to whether the vendor has requested payment of such penalty, and shall be accompanied by a notice stating the amount of the interest penalty, the number of days late and the rate used;

The invoice number or other agreed upon transaction reference number assigned by the vendor should be included in the notice to assist the vendor in reconciling the payment. Additionally, it is optional as to whether or not an agency includes the contract number in the notice to the vendor;

The temporary unavailability of funds does not relieve an agency from the obligation to pay these interest penalties or the additional penalties required under § 1315.11; and

Agencies shall pay any late payment interest penalties (including any additional penalties required under § 1315.11) under this part from the funds available for the administration of the program for which the penalty was incurred. The Prompt Payment Act does not authorize the appropriation of additional amounts to pay penalties.

Penalties not due. Interest penalties are not required:

When payment is delayed because of a dispute between a Federal agency and a vendor over the amount of the payment or other issues concerning compliance with the terms of a contract. Claims concerning disputes, and any interest that may be payable with respect to the period, while the dispute is being settled, will be resolved in accordance with the provisions in the Contract Disputes Act of 1978, (41 U.S.C. 601 et seq.), except for interest payments required under 31 U.S.C. 3902(h)(2);

When payments are made solely for financing purposes or in advance, except for interest payment required under 31 U.S.C. 3902(h)(2);

For a period when amounts are withheld temporarily in accordance with the contract;

When an EFT payment is not credited to the vendor's account by the payment due date because of the failure of the Federal Reserve or the vendor's bank to do so; or

When the interest penalty is less than $1.00.