(2) a petition to modify the child support order has been denied on the merits for a reason other than lack of timeliness.
The order described in subsection (b)(2)(B) does not include an order solely concerned with custody, parenting time, or other issues ancillary to the amount of child support, or an order that merely construes an existing order for child support, even if the order refers to or relates back to the order for child support.