(a) If a proportion of the obligor's social security benefit is paid directly to the custodian of his or her dependents who are the subject of the child support order, the following adjustment shall be made. The total amount of the social security benefit which includes the amounts paid to the obligor and the obligee shall be counted as gross income to the obligor. In turn, the child support order will be calculated as described in sections 13-401 through 13-404. To arrive at the final child support amount, however, the amount of the social security benefits sent directly to the child's household will be subtracted from the child support order. If the child support order amount results in a negative amount it shall be set at zero.
(b) If a child is a recipient of disability payments as supplemental security income for aged, blind and disabled, under the provisions of 42 U.S.C. §1382, et seq., and if support furnished by an obligor would be considered unearned income that renders the child ineligible for disability payments or medical benefits, no child support order shall be entered for that child. If a support order is entered for the child's siblings or other persons in the household, the child shall be excluded from the calculation of support, and the amount of support for the child shall be set at zero.