This regulation applies only to the Correctional Officers' Retirement System, the Employees' Retirement System, the State Police Retirement System, and the Teachers' Retirement System. Except as provided in §§D and E of this regulation, the average final compensation of a member who became a member before July 1, 2011 equals the average annual earnable compensation of the member, adjusted as provided in Regulation .04 of this chapter, for the: 3 years of employment as a member during which the member's earnable compensation was highest, if the member was employed at least 3 years as a member; or Member's total period of employment, if the member was employed less than 3 years as a member. Except as provided in §§D and F of this regulation, the average final 5 years of employment as a member during which the member’s earnable compensation was highest, if the member was employed at least 5 years as a member; or Member’s total period of employment, if the member was employed less than 5 years as a member. An increase of more than 20 percent to a member’s average annual earnable compensation in any one of the last 3 years of employment for a member who became a member before July 1, 2011, or in any one of the last 5 years of employment for a member who became a member on or after July 1, 2011, is an extraordinary salary increase that is not included in determining the member’s average final compensation unless: The increase is the result of the member’s: Promotion by the member’s employer; or Appointment or election to a public office; Including the increase when determining the member’s average final compensation would increase the member’s allowance by $25 or less per month; or The Board of Trustees determines that the increase is not an extraordinary salary increase in accordance with Regulation .05 of this chapter. If a member of the State Police Retirement System who became a member before July 1, 2011 and who transferred from another actuarial retirement system in the State retires after less than 3 years of employment as a member of the State Police Retirement System, the member’s earnable compensation in the other system shall be used to determine the member’s average final compensation. If a member of the State Police Retirement System who became a member on or after July 1, 2011 and who transferred from another actuarial retirement system in the State retires after less than 5 years of employment as a member of the State Police Retirement System, the member’s earnable compensation in the other system shall be used to determine the member’s average final compensation.