Per, I fully understood what you were saying, but merely quoted you back.
As to curve shapes, Ansco 130 and Liquidol are similar giving more open shoulders when compared to Dektol as the reference. The upper curve bends more but has the same Dmax. The result is an open shadow with more detail. So, they have hints there of something in the blacks. Very often, you must make side by side comparisons to see it.
A soft toe will make detail in highlights pop out at you strongly. This is usually only achieved in an emulsion or with severre split grade printing. The toe region is exposed as a grade 0 or 1, and the shoulder as a grade 0 or 1 with the mid scale at 2. The latter can be done in developers, but not as much for the former. It can all be done with split grade printing but takes a really superb artist in the darkroom. It can also be done in the emulsion, but then it is permanent for the entire batch of coating. Again, it takes an artist in the darkroom.
I can do this to order. But, this isn't an ad. I don't do it at all except for testing an emulsion recipe. This also goes for my developer formulations..
If you look on the Azo evaluation thread, there is a post of the Azo curve. It shows those characteristics which I have noted here, namely a rolled over shoulder and a soft toe compared to Lodima. In this case, it also includes the fact that the Lodima is about one grade higher than the Azo so this is not exactly what I am talking about, but it is close.
PE