"Does it mean that if I were interested in an aerodrome, or to Scottish, I should be encouraged to deliberately fail ?"
In the past there may have been some justification for believing this to be the case. It certainly created alot of bad feeling at LATCC where failure was perceived to have been rewarded with a prefered posting. However, second chances are far rarer these days and Trainees no longer have an Aerodrome rating to fall back on.