The Association may have the regular dues of its members within the representation unit deducted from employees’ paychecks under procedures prescribed by the County Controller. Dues deduction shall be made only upon signed authorization from the employee upon a form furnished by the County, and shall continue: (1) until such authorization is revoked, in writing, by the employee; or (2) until the transfer of the employee to a unit represented by another employee organization. Employees may authorize dues deductions only for the organization certified as the recognized employee organization of the unit to which such employees are assigned.