The subrecipient shall state the basis of its nonconcurrence with the audit finding by letter, within sixty calendar days (inclusive of the thirty calendar days allowed the subrecipient to notify the superintendent of public instruction of its concurrence or nonconcurrence provided in WAC 392-115-105) of notification from the superintendent of public instruction of the audit finding. The letter shall set forth in full the reasons for the nonconcurrence and be the basis for any subsequent review by the superintendent of public instruction. The subrecipient shall have the burden of proof in cases of disputed audit findings.