§ 34. Payment of tax. Each taxpayer shall, at the time of filing its
return, pay to the director of finance

(a) the amount of tax payable hereunder as the same shall appear from
the face of the return, or

(b) if payments of estimated tax have been made pursuant to section
thirty-five of this part, the balance, if any, of the tax payable
hereunder, as the same shall appear from the face of the return, after
applying thereto any payments made pursuant to said section.
If the time for filing the return shall be extended, the taxpayer shall
pay in addition interest at the rate of six percentum per annum from the
time when the return was originally required to be filed to the time of
payment upon the amount by which the tax, or the portion thereof payable
when the return was required to be filed, exceeds the amount then paid:

(1) a payment made on or before the date of filing of an application
for an automatic extension shall be deemed properly estimated if it is
either (A) not less than ninety percentum of the tax as finally
determined, or (B) 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.