Georgia Code Title 48. Revenue and Taxation § 48-7-34

If any corporation or nonresident employs in its books of account a detailed allocation of receipts and expenditures which reflects more clearly than the processes or formulas prescribed by this chapter the income attributable to the trade or business within this state, application for permission to base its return upon the books of account shall be considered by the commissioner. The application shall be made at least 60 days prior to the last day on which the taxpayer's return is to be filed and shall be accompanied by a full and complete explanation of the method employed.