Formulae 2 to 6 are variations of the basic formula (Formula 1, see 1.3 above).
Formulae 2, 5, and 6 apply where a non-parent is a carer of the child(ren). The way in which the parent's or parents' income is considered depends on the circumstances. Some or all of the cost of the child may be paid to the non-parent carer, depending on the care arrangements.
Formula 3 applies where at least one of the parents has multiple child support cases, but there is no non-parent carer.
Formula 4 applies where at least one of the parents has multiple child support cases and there is a non-parent carer.
These formulae use the same concepts and components as Formula 1, but have additional components to recognise the parent's financial responsibility for children in other child support cases, or to direct child support to a non-parent carer where appropriate. The multi-case allowance, a formula component that recognises responsibility for children in other cases, may also be modified through orders and agreements.
Around 90% of assessments will use Formula 1. Note that if neither parent has another child support case and there is no non-parent carer, Formula 1 applies, regardless of their care arrangements. Under the new formula, children in shared care (50/50) and divided care (one child with each parent) arrangements constitute a single case, so long as they have the same two parents, rather than two "reverse cases", as before July 2008 (see chapter 1.3).
For further information, including about how liabilities are calculated for multiple cases, refer to the Child Support Agency website www.csa.gov.au.