Each retailer selling cigarettes within the City of Los Angeles shall collect the tax imposed under Sec. 21.8.2 of this article, and on or before the last day of the month following the close of a calendar quarter remit the total amount so collected to the Director of Finance, together with a statement on a form provided by the Director of Finance showing the number of cigarettes sold to purchasers, the amount of tax collected, and such other information as the Director of Finance shall require. Where the Director of Finance determines that efficiency in the administration of the tax would be promoted, the Director of Finance may establish reporting periods greater than quarterly, but not to exceed one year. The Director of Finance may establish shorter reporting periods for any retailer if the Director of Finance deems it necessary in order to insure collection of the tax. Statements and payments are due immediately upon cessation of the business of selling cigarettes for any reason. All taxes collected by retailers pursuant to this article shall be held in trust for the account of the City until payment thereof is made to the Director of Finance.