Under section 502(d) of the act (53 P.S. § 6924.502(d)), a declaration of estimated tax of an individual having an estimated gross income from farming for the taxable year which is at least 2/3 of the individual's total estimated gross income for the taxable year may be filed at any time on or before January 15 of the succeeding year, but if the individual files a final return and pays the entire tax by March 1, the return may be considered as the individual's declaration due on or before January 15.
12 Pa. Code § 151.4