I don’t quite understand what you want to do, but i see this as potential problems:
If you want your pink rectangle to grow with the keyframes, use this expression on the size of the rectangle
m=thisComp.layer("Animation Duration").effect("Animation Duration main bar")("Slider")
linear(m,0,100,[0,150],[1800,150])
If you want the text to grow as the rectangle grows, use this expression on the text source
Math.floor(thisComp.layer("Animation Duration").effect("Animation Duration main bar")("Slider"))+"%"
Maybe change the color so the bar si different.
If you want the text to grow with the first bar, use this expression on the source text
Math.floor(thisComp.layer("Animation Duration").effect("Animation Duration BG CR")("Slider"))+"%"
Now, if you decide to stop the rectangle an some percent, both the text and the rectangle will act accordingly.
Otherwise, you will have to explain better your problem.
All the best
Andrei