The board of examiners shall determine reasonable rates of allowance for per diem subsistence for officers, agents and employees of the state who are absent from their post of duty on official business in a foreign country. In determining such rates of allowance, the limitations of section 67-2008, Idaho Code, shall not apply. The board shall determine rates of allowance which are reasonable based upon factors such as the prevailing cost of executing such travel, generally prevailing economic conditions, and the rates of allowance made applicable to similar travel by the federal government and private employers within the state.