How old are your training notes? In the good old days of steam driven instruments, the standard VOR/ILS display had a fixed needle presentation:
With this display, it was necessary to have a "backcourse" switch, in order to reverse the sense of the needle when travelling "backwards" down the beam on a backcourse approach. When the HSI presentation was introduced:
Which is the same presentation graphically reproduced on the EFIS, the backcourse switch became redundant, as the entire deviation display is "upside down" when flying the backcourse - and this naturally reverses the sense of the deviation indicator.