The Indiana child support guidelines are based upon the Income Shares Model. The following steps are followed when determining the appropriate amount of child support to award the custodial parent: The gross incomes of both parents are combined, with a percentage of shared income for each parent determined; The total is reviewed against the support tables provided by the Indiana government website to determine the total cost of supporting the child, or children involved in the divorce case; Relevant child care expenses and the cost of health insurance premiums are added to the base figure determined in step 2; The total child support figure is prorated between the parents based upon their share of the weekly adjusted incomes. Child support cannot be modified within the state of Indiana unless the financial figure being requested is greater than 20% different than what was originally ordered by the courts or the courts deem the amount to be unreasonable and unsustainable.