Agree with billm.
With 50-50, the assumption is that both households will spend THE SAME amount on child-related expenses. e.g. clothing, shelter, food, recreation. However, the purpose of the offset payment is for the higher earner to subsidize the lower earner. Both parents should be showing about the same amount of purchases for the child.
All these people who are saying that clothing is included in the CS paid ... just think about the situation where the offset CS payment is very small because the parents' incomes are close. Does that mean only a teeny amount of money is spent on clothes? No - that would be absurd (kind of like the assumption that the 39% parent spends $0 on the child).
However ... the bulk of kid expenses are specific to the household
- food, shelter (portion of mortgage/property tax/insurane/maintenance etc), transportation (portion of car loan, gas, insurance etc), vacation, computer, school supplies. So each parent just pays there own share of these.
Clothing is one area that can vary widely e.g. one parent might tend to buy the bulk of clothing, and distribute it between the households, and the other parent would pay 50% of it. Or maybe not i.e. each parent is buying their own set of clothing.
A few things there might or might not be only be one of, depending on how 'intermingled' the houses are e.g. phone, musical instrument, sports equipment. If there's only one, then share the cost if the other parent wants to have the use of it at their house too.