(a) Unauthorized loan amount. The unauthorized loan amount will be the unauthorized principal plus any interest accruing on the unauthorized principal at the note interest rate until the date paid unless otherwise agreed in writing by Rural Development.

(b) Unauthorized grant amount. The unauthorized amount will be the unauthorized grant amount actually expended under the grant agreement plus interest accrued beginning on the date of the demand letter at the interest rate stipulated in the applicable grant agreement, or, if none is stated, the default rate established by the U.S. Department of the Treasury, until the date paid unless otherwise agreed in writing by Rural Development.