S.C. Code Ann. § 12-60-410

The department shall assess state taxes, including interest, additions to taxes, and penalties. An assessment is made by an employee of the department recording the liability of the taxpayer in the office of the department in accordance with the procedures of the department. Upon request of the taxpayer, the department shall furnish a copy of the assessment. The department, at any time within the time period for assessment, may make a supplemental assessment when it is determined that an assessment is imperfect or incomplete. Except in the case of fraud, an order abating a jeopardy assessment, or additional assessments resulting from adjustments made by the Internal Revenue Service, the department may not assess taxes imposed by the same article, or chapter if the chapter has no article, for a tax period for which a final order has been issued by the Administrative Law Court or a court determining the taxpayer's liability for that tax period.