The title is maybe a little difficult to understand. I’ll try to explain giving an example:
I have two copies that are slightly different and I want to e.g. make two b/w images that will show the difference of representation of colors - the red or green balloons in this example.
When I now apply a film simulation (or monochrome toning), the channel mixer sliders work exactly the same. All customizing seem to be obsolete. If we had a feature that allowed us to make snapshots of the two images (freeze the settings) and work from there on like they were original raw files, we would open a wide range of creative possibilities. This basically means that we could work without having to go from raw to tiff (or jpg), saving some disk space and allowing us to somehow force the sequence in which settings are applied.
My personal benefit of such a function would be in negative conversions, where sliders would again behave normally. It would also ease the answer to the question asked elsewhere (here) and therefore make easier the use of DPL.