the amount of wages

For purposes of applying tables or procedures prescribed under paragraph (1), the term “the amount of wages” means the amount by which the wages exceed the number of withholding exemptions claimed multiplied by the amount of one such exemption. The amount of each withholding exemption shall be equal to the amount of one personal exemption provided in section 151(b), prorated to the payroll period. The maximum number of withholding exemptions permitted shall be calculated in accordance with regulations prescribed by the Secretary under this section, taking into account any reduction in withholding to which an employee is entitled under this section.

For purposes of applying tables or procedures prescribed under paragraph (1), the term "the amount of wages" means the amount by which the wages exceed the taxpayer's withholding allowance, prorated to the payroll period.