Elements pre/post fader to Master FX seem not to work

I was testing the pre/post fader to Master FX in Montage, and tried to set it pre or post: there’s no audio difference, but the meters of the plug-ins in the Master FX are displaying different levels visually.
Where am I wrong? Am I using the pre/post fader the wrong way?

Many thanks

What do you mean with “pre/post fader”? What option are you speaking about?

Please see the picture, maybe I got it all wrong… thanks!

The audio level is changed after the effects, or before, according to this switch.
You can see this clearly eg. if you take a plugin such as the new Steinberg Brickwall Limiter.

Absolutely right, my fault, I don’t know why I expected some “FX send” effect.