S.C. Code Ann. § 12-60-410
The department shall assess all 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 rules or procedures prescribed by the department. Upon request of the taxpayer, the department shall furnish a copy of the assessment. The department may, at any time within the time period for assessment, 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 any tax period for which a final order has been issued by the Administrative Law Judge Division or a court determining the taxpayer's liability for that tax period.