Upon the written request of the commission made to the governing body, the governing body may levy and collect an annual special improvements tax on taxable real estate zoned for commercial or industrial use or used for such purposes and taxable leasehold interests in that portion of the improvement district within its jurisdiction. For the purposes of this chapter, real property that is zoned to permit multiunit residential use but not yet used for that purpose and multiunit residential real property that is primarily leased or rented to residential tenants or other occupants by an owner who is engaged in such a business shall be deemed to be property in commercial use and therefore subject to the special improvements tax authorized by this section. Notwithstanding the provisions of Article 4 (§ 58.1-3229 et seq.) of Chapter 32 of Title 58.1, the tax shall be levied on the assessed fair market value of the taxable real property. The rate of the special improvements tax shall not be more than 40 cents ($0.40) per $100 of the assessed fair market value of any taxable real estate or the assessable value of taxable leasehold property as specified by § 58.1-3203; however, if all the owners in any district so request in writing, this limitation on rate shall not apply. Such special improvements taxes shall be collected at the same time and in the same manner as the county’s taxes are collected, and the proceeds shall be kept in a separate account. The effective date of the initial levy shall be, at the discretion of the governing body, either (i) January 1 of the year following adoption of the resolution creating the district or (ii) on a prorated basis for the period from the date when the special improvements tax was first imposed through the remainder of the year. All revenues received by the county pursuant to such taxes shall be paid to or at the direction of the district commission for its use pursuant to this chapter. All revenues generated from the annual special improvements taxes levied by the governing body pursuant to this section shall be deemed to be contributions of that governing body in any transportation cost-sharing formula.