(A) A taxpayer's method of accounting under this chapter must be the same as for federal income tax purposes.
(B) If a taxpayer's method of accounting is changed for federal income tax purposes:
(1) The method of accounting for South Carolina income tax purposes is changed. The taxpayer shall provide the department with a copy of the written permission received from the Internal Revenue Service. When written permission is not required to change a method of accounting, the taxpayer shall provide the department with a copy of the election or statement provided to the Internal Revenue Service.
(2) Additional South Carolina income or deductions which result from adjustments that are necessary because of a change in the method of accounting are included in or deducted from income as provided in the Internal Revenue Code.