(1) Any employee of the Arkansas State Highway and Transportation Department or the Arkansas Department of Transportation who is a member of the Arkansas State Highway Employees' Retirement System and who has served as a member of the State Highway Commission shall receive partial credit, equal to forty percent (40%) of the time the member served as a member of the commission, as creditable service.
(2) For the purpose of calculating the member's annuity, the portion of creditable service attributed to serving on the commission shall not be considered when determining retirement eligibility, nor shall it be considered when calculating the annuity, but it is to be considered only toward vesting in the system.