It is correct that ReMines’ model is not mainstream. But to be clear, I am not saying that “because he is wrong, so are you.” I bring him up to point out that “design” is a broad concept that includes several models. Some of these models make entirely different predictions than you are making. I even was sure to point out that your model produces different predictions than his (blue vs orange curve).
And, I have already sketched out the principles behind CD. It depends on another variable: the rate of change. It is fairly easy to see how this enables us to compute the expected range of CI we can expect for a given feature.
At this point, however, you have not specified your model. Please explain to us: what is your model of design? Clearly, it is not ReMine’s model, but what is it exactly? And how does it give rise to your precise CI predictions with narrow standard deviation? What is the math/principles/calculations you use to arrive at the expected consistency? Just saying “design” is very poorly specified, which is why you ended up on the orange curve.