It is not a common event for a Court to impose a child support obligation on a parent at a level which exceeds the statutory guidelines- the statutory section is helpful on this (see prior comment). However, the cases where the deviation is granted is usually when (1) there is a highly disparate level of incomes between the parents which is not the result of fault on the part of the parent who is earning less AND the family history of living-style was at the higher level (2) there is evidence that implies strongly to the Court that a parent is being less than honest about that parent's assets and financial abilities to pay or (3) there is a significant need in the child's life which is so unusual (often severe medical issues) which one parent can manage to take care of while the other is unable to do so. But usually it's #2, the 'imputation of income' situation to a parent who (for example) quit being a rocket scientist (just because he wanted to) and took up carpentry, thereby dropping her annual income by 90%- that is a classic case where the actual annual income will be ignored by a Court, and income at the higher former rate imputed to that parent.
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