A. When a contractor has paid any local license tax required by the county, city or town in which his principal office and any branch office or offices may be located, no further license or license tax shall be required by any other county, city or town for conducting any such business within the confines of this Commonwealth. However, when the amount of business done by any such contractor in any other county, city or town exceeds the sum of $25,000 in any year, such other county, city or town may require of such contractor a local license, and the amount of business done in such other county, city or town in which a license tax is paid may be deducted by the contractor from the gross revenue reported to the county, city or town in which the principal office or any branch office of the contractor is located.
B. Any contractor, as defined in § 58.1-3714 D, conducting business in a county, city or town for less than thirty days without a definite place of business in any county, city or town of the Commonwealth shall be subject to the license fee or license tax imposed on contractors by any county, city or town, where the amount of business done by the contractor in such county, city or town exceeds or will exceed the sum of $25,000 for the license year. That portion of the gross receipts of a contractor subject to the license tax pursuant to this subsection shall not be subject to such tax in any other county, city or town.