In the early days of reduced thrust takeoffs, Qantas changed its procedures to limit reduced thrust to the relevant climb setting after a crew thought it strange that they had to increase thrust at the climb reduction point during the takeoff. The performance boss at the time (Wal Stack) concurred and the limitation was applied .. this probably goes back to the early 60s .. I can recall Wal's relating the tale when I was a student in the late 60s and he was a department Industry lecturer.