S.C. Code Ann. § 12-8-1060 — Estimated quarterly payments by employer of withholding

The department may authorize employers to:
(1) estimate the wages that are paid to an employee in a quarter of the calendar year;
(2) determine the amount to be withheld on each payment of wages during the quarter as if the appropriate average of the estimated wages is the actual wages paid; and
(3) withhold on a payment of the employee's wages during the quarter the amount necessary to adjust the estimated amount withheld to the actual amount required to be withheld during the quarter as if the payroll period of the employee was quarterly.