Section 1516. Payment of tax

(a) To the extent the tax imposed by this
  article shall not have been previously paid pursuant to section  fifteen
  hundred fourteen,
    (1) each such tax, or the balance thereof, shall be payable to the tax
  commission  in  full at the time the taxpayer's return is required to be
  filed, and
    (2) each such tax, or the balance thereof,  imposed  on  any  taxpayer
  which  ceased  to  exercise  its  franchise  or to be subject to the tax
  imposed by this article shall be payable to the tax  commission  at  the
  time  the  return  is  required to be filed, provided each such tax of a
  domestic corporation which continues to possess its franchise  shall  be
  subject  to adjustment as the circumstances may require; all other taxes
  of any such taxpayer, which pursuant to the foregoing provisions of this
  subdivision would otherwise be  payable  subsequent  to  the  time  such
  return  is  required  to be filed, shall nevertheless be payable at such
  time.
    (b) If the taxpayer, within the time prescribed by subdivision (c)  of
  section  fifteen  hundred  fifteen,  shall have applied for an automatic
  extension of time to file its annual return and shall have paid  to  the
  commissioner  of  taxation  and  finance  on  or  before  the  date such
  application is filed an amount properly estimated as  provided  by  said
  subdivision,  the  only  amount  payable in addition to the tax shall be
  interest at the underpayment rate set by the  commissioner  pursuant  to
  subsection (e) of section one thousand ninety-six or, if no rate is set,
  at  the  rate of six percent per annum upon the amount by which the tax,
  or portion thereof payable on or before the date the return was required
  to be filed, exceeds the  amount  so  paid.  For  the  purposes  of  the
  preceding sentence,
    (1)  an  amount  so  paid  shall be deemed properly estimated if it is
  either  (i)  not  less  than  ninety  percent  of  the  tax  as  finally
  determined, or (ii) not less than the tax shown on the taxpayer's return
  for  the  preceding  taxable  year, if such preceding year was a taxable
  year of twelve months; and
    (2) the time when a return is required to be filed shall be determined
  without regard to any extension of time for filing such return.
    (c) The tax commission may grant a reasonable extension  of  time  for
  payment  of  any tax imposed by this article under such conditions as it
  deems just and proper.