Section 28. The first justice of the Suffolk county court may, subject to the approval of the chief justice of the probate and family court, appoint a clerk who may administer the oaths required in probate proceedings that are not prescribed by law to be administered by the judge or register and shall perform such clerical and other duties as may be required by the first justice. The clerk may be removed by the first justice, with the approval of the chief justice. The register of probate may designate 6 employees as deputy assistant registers with the same powers as assistant registers and may revoke such designation at will. A deputy assistant register shall receive as additional compensation an amount equal to 15 per cent of the annual salary of the Suffolk county register of probate. The register may designate 6 employees as associate deputy registers who shall have the powers of assistant registers and receive as additional compensation an amount equal to 7.5 per cent of the salary paid to the register. The register may revoke any such designation at will.