Any person who on June 30, 1998, was an active, inactive, or retired member of a predecessor retirement system shall be transferred to this retirement system in the same status effective July 1, 1998. Any person who on June 30, 1998, was a beneficiary of a predecessor retirement system shall become a beneficiary of this retirement system in the same status effective July 1, 1998; provided, however, that, except as otherwise expressly provided, the benefits of any beneficiary so transferred shall continue to be calculated as such benefits were calculated on June 30, 1998.