(a) The declaration required by Section 157.1303 shall be filed upon a form furnished by or obtainable from the Administrator. As provided in Section 157.1303, credit shall be taken for the City tax to be withheld from any portion of such income and credit shall be taken for tax to be paid or withheld and remitted to another taxing municipality, in accordance with the provisions of Section 157.1902.
(b) The original declaration or any subsequent amendment thereof may be increased or decreased on or before any subsequent quarterly payment date as provided for herein.