The court shall review the work-related and
education-related child care costs paid and shall allocate the
costs to each parent in proportion to each parent's net income,
as determined under this subdivision, after the transfer of
child support and spousal maintenance, unless the allocation
would be substantially unfair to either parent. There is a
presumption of substantial unfairness if after the sum total of
child support, spousal maintenance, and child care costs is
subtracted from the obligor's income, the income is at or below
100 percent of the federal poverty guidelines.