(a) Each employee in a compensation level of the House Employees Schedule (HS), who has not attained the highest scheduled rate of compensation for the compensation level (HS level) in which his position is placed, shall be advanced successively to the next higher step of such HS level, as follows:

(1) to steps 2, 3, and 4, respectively—at the beginning of the first pay period following the completion, without break in service of more than thirty months, of one year of satisfactory service in the next lower step;

(2) to steps 5, 6, and 7, respectively—at the beginning of the first pay period following the completion, without break in service of more than thirty months, of two years of satisfactory service in the next lower step;

(3) to steps 8, 9, and 10, respectively—at the beginning of the first pay period following the completion, without break in service of more than thirty months, of three years of satisfactory service in the next lower step; and

(4) to steps 11 and 12, respectively—at the beginning of the first pay period following the completion, without break in service of more than thirty months, of five years of satisfactory service in the next lower step.

(b) The receipt of an increase in compensation during any of the waiting periods of service specified in subsection (a) of this section shall cause a new full waiting period of service to commence for further step increases under such subsection.

(c) Any increase in compensation granted by law, or granted by reason of an increase made by the committee in the rates of compensation of the House Employees Schedule, to employees within the purview of subsection (a) of this section shall not be held or considered to be an increase in compensation for the purposes of subsection (b) of this section.

(d) The benefit of successive step increases under subsection (a) of this section shall be preserved, under regulations prescribed by the committee, for employees whose continuous service is interrupted by service in the Armed Forces of the United States.

(e) The committee shall establish and maintain, and, from time to time, may revise, a system of automatic advancement, by successive step increases in compensation, on the basis of satisfactory service performed, without break in service of more than thirty months, for employees subject to the House Wage Schedule (HWS). In the operation of such system of step increases the committee may prescribe regulations to the effect that—

(1) the receipt of an increase in compensation during any of the waiting periods of service required for advancement by step increases under such system shall cause a new full waiting period of service to commence for further step increases under such system;

(2) any increase in compensation granted by law, or granted by reason of an increase made by the committee in the rates of compensation of the House Wage Schedule, to employees within the purview of such system of step increases shall not be held or considered to be an increase in compensation for the purposes of subparagraph (1) of this subsection; and

(3) the benefit of successive step increases under such system of step increases shall be preserved, under regulations prescribed by the committee, for employees whose continuous service is interrupted by service in the Armed Forces of the United States.