If the OALJ accepts jurisdiction of a case under § 81.38, the recipient shall present its case first and shall have the burden of proving that the recipient is not required to return the amount of funds that the disallowance decision requires to be returned because—

(a) An expenditure identified in the disallowance decision as unallowable was allowable;

(b) The recipient discharged its obligation to account properly for the funds;

(c) The amount required to be returned does not meet the standards for proportionality in § 81.32;

(d) The amount required to be returned includes an amount attributable to mitigating circumstances under the standards in § 81.33; or

(e) The amount required to be returned includes an amount expended in a manner not authorized by law more than five years before the recipient received the notice of the disallowance decision.