I admit I have not looked at a 320 fcom as I have not flown a 320 so my brave pronouncement may well be just that, brave! Nevertheless I have not seen it in the 737, 777, 330, and sundry smaller jets. Doesn't mean it isn't there just not seen it.
I tend to pay as much or more attention to the back of the engine as I can see the back of the fan blades and into the back of the engine,where looking in through the front isn't as easy.
All I was getting at is that this "procedure" isn't as universally accepted as perhaps some think and don't look down on those that don't accept it as a gospel truth.