Sec. 1.5. (a) The department may issue a refund or credit without a taxpayer filing a refund claim in the event of:
(1) an error by the department;
(2) an error determined by the department; or
(3) a taxpayer's overpayment determined by the department under an audit or investigation.
(b) The department shall prescribe rules or guidelines to govern the circumstances under which the department may issue a refund or credit under this section.
(c) The department may not issue a refund or credit under this section if the period for filing a refund claim under this article has expired before the issuance of the refund or credit.
(d) Nothing in this section shall constitute a requirement that the department issue a refund or credit for an overpayment.