The calculation: both parents' net incomes combine, the statutory schedule sets the basic obligation, add-ons (children's insurance, work-related child care) get shared by income percentage, and substantial time-sharing (at least 20% of overnights each) switches to the gross-up method.
The real fights are the inputs: what counts as income, imputed income for voluntary underemployment, self-employment accounting, and the actual overnight count.
Support runs until 18 (or high-school graduation within limits) and can extend for dependent adult children. Enforcement runs through income withholding, the depository system, license suspension, and civil contempt.