“204b” originated from the Postal Field Service Compensation Act [Public Law 84–68] that took effect on 12-03-1955. It meant higher level. Section 204(b) said:
As the needs of the service require, an employee may be assigned from time to time to perform, without change in compensation, duties, and responsibilities other than the duties and responsibilities specifically set forth in his position description; however, if any employee is assigned for more than thirty days in any calendar year to duties and responsibilities of a salary level which is higher than the salary level to which his position is assigned, except to perform service in a relief capacity for a supervisor granted compensatory time pursuant to section 603, he shall be paid for the period of his assignment in excess of thirty days a basic salary computed in accordance with the provisions of section 502.
Detailed instructions for implementing Sec. 204(b) were published in the Postal Bulletin 19936, dated 4-12-1956, in an article titled “Application of Section 204(b), Public Law 68, to Service in Higher Level Positions.” It applied to the entire Postal Field Service from Janitor (PFS-1) to Regional Director (PFS-20). Clerks and city carriers were PFS-4s. I worked in 204(b) higher level assignments in the 1960s. It didn’t mean supervisor. Former Clerk Craft Director Robert Tunstall used to remind people of that. These documents are attached.