at rates authorized for employees of agencies under subchapter I of chapter 57 of title 5, United States Code, while away from their homes or regular places of business in the performance of services for the Commission. (c) Staff Subject to such rules as the Commission may prescribe, the Chairperson of the Commission, without regard to the provisions of title 5, United States Code, governing appointments in the competitive service, and without regard to the provisions of chapter 51 and subchapter III of chapter 53 of such title (relating to classification and General Schedule pay rates), may appoint and fix the pay of a staff director and such other personnel as may be necessary to enable the Commission to carry out its functions