(f) The period of overpayment during which interest shall be allowed shall not include any period during which an agreement between the taxpayer and the Internal Revenue Service was not filed as required by subsection (6) of section 77-2786 and the first ninety days after such agreement is filed.
(3)(a) Except as provided in subdivision (b) of this subsection, if any overpayment of income tax imposed by the Nebraska Revenue Act of 1967 is refunded within ninety days after the last date prescribed, or permitted by extension of time, for filing the return of such tax or within ninety days after any original return, and any amended return filed to carry back a loss, was filed, whichever is later, no interest shall be allowed under this section on overpayment.
(b) If the Tax Commissioner approves and implements an electronic form or method for filing the return and the return is not filed electronically, no interest shall be allowed under this section on overpayment.
(c) In the case of amended returns filed for any reason other than to carry back a loss, interest shall be allowed as provided in subsection (1) of this section.