It is likely the tanning process which helps slightly. In any case ABC (Kodak D-1) doesn't produce such heavy stain unless you alter the dilution for less sulfite. Kodak later came up with formulas which were designed for more imagewise staining.
I'll also throw in my white elephant for the fun of it: why anyone would bother in this day and age with DBI versus time/temperature control is beyond me. In the days of Weston it made some more sense because light meters were primitive, and materials were subject to more variability (film speeds, developer activity, etc.). At this point, what value can it possibly add?
Oh, I agree. But in the same token, a lot of the discussions here are of that nature - interesting but often times not adding much, if any, value to the actual practice of darkroom photography.
I find that by keeping things as simple as possible, I reach higher and farther with my photography. But it's still interesting to learn, even about things I will never use. It helps paint a bigger picture, and better understand the things I do use, and it throws perspective on those processes that I'm tempted to try, as well as their actual utility.
And cool factor.
