In accordance with the rulemaking and regulationmaking requirements of the Administrative Procedure Act, the Attorney General shall prepare and promulgate model rules of procedure appropriate for use by as many agencies as possible and shall file the model rules with the Secretary of State. The model rules shall deal with all general functions and duties performed in common by several agencies. For rules of procedure adopted on or after August 1, 1994, each agency shall adopt as many of the model rules as is practicable under its circumstances. To the extent an agency adopts the model rules, it shall do so in accordance with the rulemaking and regulationmaking requirements of the act. Any agency adopting a rule of procedure that differs from the model rules shall include in the explanatory statement provided for in section 84-907.04 a finding stating the reasons why the relevant portions of the model rules were impracticable under the circumstances.