Section 11-706. Payment of tax

a. The tax imposed by this chapter shall be
  due and payable on or before the twentieth day  of  the  calendar  month
  following  the  end  of  each  tax  period  and  shall  be  paid  to the
  commissioner of finance, as follows: The tax to be  paid  at  such  time
  shall  be based on the base rent for such tax period and the rate of tax
  shall be the one which would be applicable if the  base  rent  for  such
  period  were  the  same  for each tax period during the tax year, except
  that the payment required to be made together with the final  return  or
  at the time that the final return should be filed shall be the amount by
  which  the  actual  tax  for the tax year exceeds the amounts previously
  paid for the tax year.
    b. Where the final return shows that the amount of tax  paid  for  the
  tax  year  exceeds  the  actual  tax  for such year, the commissioner of
  finance shall make the  appropriate  refund  as  promptly  as  possible,
  provided,  however, that where the commissioner of finance has reason to
  believe that the  final  return  is  inaccurate,  the  commissioner  may
  withhold the refund in whole or in part. The making of a refund pursuant
  to  this  subdivision shall not prevent the commissioner of finance from
  making a determination that additional tax is due or from  pursuing  any
  other  method  to  recover the full amount of the actual tax due for the
  tax year.
    c. Where a tenant ceases to do business the tax, as  measured  by  the
  tenant's  base  rent  for  the  prior part of the tax year, shall be due
  immediately, and the tenant shall file a final return, but,  should  the
  tenant  continue  to pay rent for the taxable premises, the tenant shall
  file the normally required returns and a final return for the tax  year,
  provided,  however,  that  any  such  tax  payment  shall  be applied in
  reduction of the tax payments required to be made with such  returns  or
  with the final return for such tax year.