Im a lawyer who acts in the Family Court, and you're wrong! Other than pointing you to the legislation, Im not sure what else I can do here.I'm aware of the legislation. The courts give little if any weight to that clause.
Do you want me to post some recent case law to highlight how wrong you are?
And the reason for that 87 percent is due to the fact that after Separation in 87 percent of cases, the woman is the one left as the primary caregiver of the children. It's often the husband that moves out of the family home and the wife that gets left with the kids as in most cases when a child is born, it's the woman who puts her career on hold to raise the children while the husband works.Note - the acts do not discriminate based on sex so we should talk about 'payees' and 'payers'. But the number of men paying child support represents about 87% of all paying parents.
If the situation was different (the husband did the stay at home dad thing while mum worked, and the wife was the one that moved out of the family home after separation) then it would likely be the father who would get the lions share of the 'custody' of the children, and the corresponding child support payments from the mother to go with it.
Most working dads are not in a position to be 50/50 or primary caregivers to children post separation. The whole 'one day a week plus alternating weekends/ school holidays thing' is often the best they can do factoring in their careers.