If the taxpayer departs from or modifies the basis for excluding or including gross receipts in the sales factor used in returns for prior years, the taxpayer shall disclose in its Arkansas return for the current year the nature and extent of the modification.
If the returns filed by the taxpayer with all states to which the taxpayer reports are not uniform in the inclusion or exclusion of gross receipts, the taxpayer shall disclose in its Arkansas return the nature and extent of the variance.
3.26 Ark. Code R. 51-715