Sec. 2.4. Except as provided in section 10.7(c) of this chapter, as used in this chapter, "gross retail base period amount" means:
(1) the aggregate amount of state gross retail and use taxes remitted under IC 6-2.5 by the businesses operating in the territory comprising a district during the full state fiscal year that precedes the date on which:
(A) an advisory commission on industrial development adopted a resolution designating the district, in the case of a district that is not described in section 12(c) of this chapter; or
(B) the legislative body of a county or municipality adopts an ordinance designating a district under section 10.5 of this chapter;
(2) an amount equal to:
(A) the aggregate amount of state gross retail and use taxes remitted:
(i) under IC 6-2.5 by the businesses operating in the territory comprising a district; and
(ii) during the month in which an advisory commission on industrial development adopted a resolution designating the district; multiplied by
(B) twelve (12);
in the case of a district that is described in section 12(c) of this chapter; or
(3) an amount equal to the amount determined under subdivision (1) or (2); plus:
(A) the aggregate amount of state gross retail and use taxes remitted:
(i) under IC 6-2.5 by the businesses operating in the territory added to the district; and
(ii) during the month in which a petition to modify the district's boundaries is approved by the budget agency under section 12.5 of this chapter; multiplied by
(B) twelve (12);
in the case of a district modified under section 12.5 of this chapter.