Sec. 6.5. (a) Except as provided in subsection (b), the court in which a petition is filed may allow the petition or cross-petition to be amended at any time upon the terms and conditions that the court orders.
(b) The court may not allow a petition to be amended following the deadline for filing a petition under this chapter if the petition as originally filed:
(1) failed to comply with this chapter; or
(2) was not filed before the deadline specified in this chapter.