(a) Where a DOT creditor operating element (see § 92.5(g)) is the creditor, it shall charge interest on an outstanding debt at the rate published by the Secretary of the Treasury in accordance with 31 U.S.C. 3717. The rate of interest assessed shall be the rate of the current value of funds to the United States Treasury (i.e., the Treasury tax and loan account rate), as prescribed and published by the Secretary of the Treasury in the Federal Register and the Treasury Financial Manual Bulletins annually or quarterly, in accordance with 31 U.S.C. 3717. The DOT creditor operating element shall charge a penalty of six percent a year, in addition to interest, on any portion of a debt that is more than 90 days past due. It shall assess administrative charges to cover additional costs incurred in processing and handling the debt beyond the payment due date. The imposition of interest, penalties and administrative charges is made in accordance with 31 U.S.C. 3717 and 4 CFR 102.13.

(b) Interest on debt shall begin to accrue on the date on which the debtor is first sent or delivered notice of the debt and of the interest requirements or, in the case of advance billings, on the calendar date following the specified due date of the debt provided the advance billing gives notice of the interest requirements for late payment. Interest on the debt shall continue to accrue until payment is received. Interest shall be calculated only on the principal of the debt (simple interest). The rate of interest charged shall be the rate in effect on the date from which interest begins to accrue, and shall remain fixed for the duration of the indebtedness.

(c) A DOT creditor operating element shall waive the monthly interest on debt that is paid within 30 calendar days after the date on which interest began to accrue.

(d) A DOT creditor operating element may waive interest, penalties and/or administrative charges if it finds that: