(1) If the due date for the payment of any tax, rent, fee or other obligation due the City falls on a Sunday or a holiday, or any day during which the agency collecting such tax, rent, fee or other obligation is not open for a full business day, the Department of Collections may postpone such due date to the next following business day.^[64]

(2) The Department may, upon proper cause shown, grant a taxpayer an extension of not more than 60 days for the payment of any tax, except real estate taxes and water and sewer rents. Application for such extension shall be made on or before the last day for the payment of the tax, is such form as the Department prescribes.^[65]

(3) If any Federal taxing authority grants to any taxpayer an extension for the payment of Federal income tax for a period in excess of 60 days, the Department may grant an additional extension of time for the payment of any City tax affected thereby, not to exceed 30 days after the termination of the Federal extension period.

(4) Where an extension for payment of any tax has been granted by the Department, the principal amount of such tax shall be subject to interest from the original due date at the rate of ½ of 1% per month, or part thereof, but shall not be subject to any penalty if paid within the extended period.