If a claim for refund is not issued within ninety (90) days of the filing required by section 32 of this chapter, the department shall pay interest at the rate established by IC 6-8.1-9 from a date that is ninety (90) days after the date that the department receives the claim for refund and all necessary documentation until a date, determined by the commissioner, that does not precede by more than thirty (30) days, the date on which the refund is made.
IC 6-6-2.5-33