N.M. Stat. § 40-4-11.2
Any deviation from the child support guidelines set forth in Section 40-4-11.1 NMSA 1978 and the basic child support schedule promulgated by the human services department [health care authority department] shall be supported by a written finding in the decree, judgment or order of child support that application of the guidelines and basic child support schedule would be unjust or inappropriate. A finding that rebuts the child support guidelines and basic child support schedule shall state the amount of support that would have been required under the guidelines and basic child support schedule and the justification of why the order varies from the guidelines and the basic child support schedule. Circumstances creating a substantial hardship in the obligor, obligee or subject children may justify a deviation upward or downward from the amount that would otherwise be payable under the guidelines and basic child support schedule.
NMS § 40-4-11.2