Va. Code § 58.1-463
The Tax Commissioner may grant permission to employers who do not desire to use the withholding tax tables provided in accordance with § 58.1-462, to determine the amount of tax to be withheld by use of a method of withholding other than withholding tax tables, provided such method will withhold from each employee substantially the same amount of tax as would be withheld by use of the withholding tax tables. Employers who desire to determine the amount of tax to be withheld by a method other than by use of the withholding tax tables shall obtain permission from the Tax Commissioner before the beginning of a payroll period for which the employer desires to withhold the tax by such other method. Applications to use such other method must be accompanied by evidence establishing the need for the use of such method.
Va. Code § 58.1-463