If I had to guess, those modules probably use the position value to generate feedback. That will always be 0.0-1.0 regardless of what the actual gain range is set to. I'm not aware of a way to get the min/max values on the standard gain block. If I have a scripting license, I have a custom gain block I use for this that has min/max controls available at run time in the block. They can be assigned named controls and read that way if needed.
-Dustin
