Section 11-808. Payment of tax

a.  At  the  time  of filing a return or
  supplemental return the owner shall pay to the commissioner  of  finance
  the tax imposed hereunder. Such tax shall be due and payable on the last
  day on which such return or supplemental return is required to be filed,
  regardless of whether such a return is filed or whether the return which
  is filed correctly indicates the amount of tax due.
    b. Where an owner of a motor vehicle subject to tax under this chapter
  replaces  it  with  another  motor  vehicle during a tax year, the owner
  shall be entitled, upon approval by the commissioner of finance, to have
  any tax paid with respect to the replaced vehicle  credited  toward  the
  tax  payable  with respect to the replacement vehicle for the balance of
  such tax year, and the owner shall pay no additional tax  for  such  tax
  year  with  respect  to it unless its nature or its maximum gross weight
  requires the payment of a higher amount  of  tax  than  that  paid  with
  respect  to the replaced vehicle. A supplemental return, where required,
  shall be filed with respect to a  replacement  vehicle  irrespective  of
  whether  additional tax is payable. Upon the grant of a waiver of tax by
  the commissioner of finance a purchaser of a motor  vehicle  subject  to
  tax  under this chapter who purchases it during a tax year from an owner
  who has paid the tax shall not be required to pay the tax  with  respect
  to  such motor vehicle for the balance of such tax year if, and only if,
  the owner obtains, and submits to the commissioner of  finance  together
  with  his  or  her  return  or supplemental return, a certificate or its
  equivalent (as prescribed by the commissioner of finance) signed by  the
  prior  owner to the effect that the prior owner has not had the tax paid
  credited toward any replacement vehicle and will not seek to obtain such
  a credit for any replacement vehicle purchased in  the  future.  Nothing
  contained  in  this  subdivision  shall  be deemed to authorize a refund
  merely because a motor vehicle with respect to which the  tax  has  been
  paid is sold or otherwise disposed of during the course of the tax year.
    c. Notwithstanding any other provision of law to the contrary, the tax
  imposed  on medallion taxicabs pursuant to subparagraph (C) of paragraph
  two of subdivision a of section 11-802 of this chapter shall be due  and
  payable  in  two equal installments, the first of which shall be due and
  payable on or before the last day on which the  return  or  supplemental
  return for the tax year is required to be filed, and the second of which
  shall  be due and payable on or before the first day of December in such
  tax year; provided, however, that if a  medallion  taxicab  is  acquired
  subsequent  to  the  first  day  of  November in such tax year, the full
  amount of the tax imposed for the tax year shall be due and  payable  on
  or  before the last day on which the supplemental return with respect to
  such medallion taxicab is required to be filed.
    d. Notwithstanding any other provision of law to the contrary, the tax
  imposed on medallion taxicabs pursuant to subparagraph (B) of  paragraph
  two  of  subdivision  a  of section 11-802 of this chapter shall, to the
  extent not previously paid, be due and payable  on  or  before  December
  first,  nineteen hundred eighty-nine; provided, however, that if the tax
  imposed on a medallion taxicab would, but for  the  provisions  of  this
  subdivision,  be  due and payable subsequent to December first, nineteen
  hundred eighty-nine, the due  date  of  such  tax  shall  be  determined
  without  regard to this subdivision; and provided, further, that nothing
  in this subdivision shall be deemed to extend the date  for  payment  of
  any  tax  imposed by paragraph two of subdivision a of section 11-802 of
  this chapter as such paragraph two was in effect  immediately  prior  to
  its amendment by the local law which added this subdivision.