D. The supreme court shall establish guidelines for determining the amount of child support.  The amount resulting from the application of these guidelines is the amount of child support ordered unless a written finding is made, based on criteria approved by the supreme court, that application of the guidelines would be inappropriate or unjust in a particular case.  The supreme court shall review the guidelines at least once every four years to ensure that their application results in the determination of appropriate child support amounts. The supreme court shall base the guidelines and criteria for deviation from them on all relevant factors, considered together and weighed in conjunction with each other, including:

1. The financial resources and needs of the child.

2. The financial resources and needs of the custodial parent.

3. The standard of living the child would have enjoyed if the child lived in an intact home with both parents to the extent it is economically feasible considering the resources of each parent and each parent's need to maintain a home and to provide support for the child when the child is with that parent.

4. The physical and emotional condition of the child, and the child's educational needs.

5. The financial resources and needs of the noncustodial parent.

6. The medical support plan for the child.  The plan should include the child's medical support needs, the availability of medical insurance or services provided by the Arizona health care cost containment system and whether a cash medical support order is necessary.

7. Excessive or abnormal expenditures, destruction, concealment or fraudulent disposition of community, joint tenancy and other property held in common.

8. The duration of parenting time and related expenses.

E. Even if a child is over the age of majority when a petition is filed or at the time of the final decree, the court may order support to continue past the age of majority if all of the following are true:

1. The court has considered the factors prescribed in subsection D of this section.

2. The child has severe mental or physical disabilities as demonstrated by the fact that the child is unable to live independently and be self-supporting.

3. The child's disability began before the child reached the age of majority.

F. If a child reaches the age of majority while the child is attending high school or a certified high school equivalency program, support shall continue to be provided during the period in which the child is actually attending high school or the equivalency program but only until the child reaches nineteen years of age unless the court enters an order pursuant to subsection E of this section.  Notwithstanding any other law, a parent paying support for a child over the age of majority pursuant to this section is entitled to obtain all records related to the attendance of the child in the high school or equivalency program.

B. If child support has not been ordered by a child support order and if the court deems child support appropriate, the court shall direct, using a retroactive application of the child support guidelines to the date of filing a dissolution of marriage, legal separation, maintenance or child support proceeding, the amount that the parents shall pay for the past support of the child and the manner in which payment shall be paid, taking into account any amount of temporary or voluntary support that has been paid. Retroactive child support is enforceable in any manner provided by law.

C. If the parties lived apart before the date of the filing for dissolution of marriage, legal separation, maintenance or child support and if child support has not been ordered by a child support order, the court may order child support retroactively to the date of separation, but not more than three years before the date of the filing for dissolution of marriage, legal separation, maintenance or child support. The court must first consider all relevant circumstances, including the conduct or motivation of the parties in that filing and the diligence with which service of process was attempted on the obligor spouse or was frustrated by the obligor spouse. If the court determines that child support is appropriate, the court shall direct, using a retroactive application of the child support guidelines, the amount that the parents must pay for the past support of the child and the manner in which payments must be paid, taking into account any amount of temporary or voluntary support that has been paid.