The goal of the Tennessee child support law is to make sure that, to the extent possible, children be afforded the same opportunities available to children of intact families consisting of parents with similar means to those of their own parents.
In other words, children deserve a certain proportion of the income available to both parents. If one parent has less income that the other, the higher-income parent will be expected to transfer funds to the lower-income parent. This is called the “income shares” model, because both parents share in the support of their children. It is based on economic studies of child-rearing costs and the model is followed in the majority of US states.
In addition to actual income, the actual expenses in raising the children are part of the calculation. So, if the lower income parent pays for the children’s medical insurance, those expenses will be fairly accounted for, in the child support calculation.