Sec. 12. (a) Except as provided in subsection (b), a municipally owned utility may, but is not required to, file a petition for a change in its initial adjustment amount not more often than one (1) time every twelve (12) months. Section 10 of this chapter applies to a petition to change an adjustment rider.
(b) Except as provided in section 15 of this chapter, a municipally owned utility may not file a petition described in subsection (a) in the same calendar year in which the utility has filed a request for a general increase in the basic rates and charges of the utility.