No rate of less than 2.7 percent shall be permitted an employing unit succeeding to the experience of another employing unit pursuant to N.H. Rev. Stat. § 282-A:91-93 for any period subsequent to such succession except in accordance with rules adopted by the commissioner, which rules shall be consistent with federal requirements for additional credit allowance in section 3303 of the Internal Revenue Code of 1954 and consistent with the provisions of this chapter; except that such rules may establish a computation date for any such period different from the computation date generally prescribed by this chapter.