I have a client who has foreign earned income, which a portion is being excluded. After the exclusion, their taxable income remaining is $30,553. ProConnect is calculating a tax liability of $7,332, but if I do the math based on the tax table, it should be $2,433. What is strange is that their marginal and effective tax rates are exactly the same (24%). Is their a rule that exists, where the remaining foreign income gets taxed at a flat 24% rate? I could not find this anywhere in the IRS tax code.