With Sinkov (US Army), the three assistant directors were Australians Alistair "Mic" Sandford (Major then Lt-Col, Second AIF) and Roy Booth (Squadron Leader then Wing Commander, RAAF). They acted as head of their respective service organisations; with Sandford the bureau executive officer under Sherr, then Booth from 1944. The bureau functioned well and harmoniously, with job demarcation as Australian experience was from wireless interception and traffic analysis in the Middle East and the Americans in breaking codes and cyphers, although this "broke down" as the war went on. Signals organisations tend to be "meritocratic" rather than on rank.