Well, I have used it both one-shot and mixed to 1:4 with multiple use and time adjustment. I found the one-shot route to be more convenient but wasteful of a now scarce and expensive developer. Results were similar from both, so I can't really say one-shot is particularly better. Arguably it will give better consistency than roll 12 on a 1 liter batch, though. It does not make sense to me to use this developer for anything but pushed fast films, or where you are desperate to drag shadow details up. Its tonality for medium and slow speed films is not in my view better than "stock standard" developers like D76 or Rodinal, and it is much more expensive than those. Still, if you want to standardise on one developer for everything, it will get the job done.