For purposes of this section, the due date for a return filed for the state gross retail or use tax, the gasoline use tax, the gasoline tax (including the inventory tax), the special fuel tax (including the inventory tax), the motor carrier fuel tax (including the inventory tax), the oil inspection fee, the cigarette tax, the tobacco products tax, any county innkeeper's taxes imposed under IC 6-9, any food and beverage taxes imposed under IC 6-9, any county or local admissions taxes imposed under IC 6-9, or the petroleum severance tax is the end of the calendar year which contains the taxable period for which the return is filed. The claim must set forth the amount of the refund to which the person is entitled and the reasons that the person is entitled to the refund.
The ninety (90) day period may be extended according to the terms of a written agreement signed by both the department and the person. The agreement must specify a date upon which the extension will terminate and include a statement that the person agrees to preserve the person's records until that specified termination date. The specified termination date agreed upon under this subsection may not be more than ninety (90) days after the expiration of the period otherwise specified by this subsection.
whichever is later.
IC 6-8.1-9-1