Polyglot, yes, the best thing is to bring back your chemicals to standard dilution and just carefully preserve the diluted chemistry.

All this makes me even more convinced that one-shot processing is the way to go. One can occasionally make mistakes during the dilution process, but then he'll only have wasted 140 ml or 250 ml of final solution.

No sooner than yesterday I made such a mistake. I diluted my first developer but I inadvertently took the chemical from the first component of the colour developer (almost identical flask). When I begun diluting the colour developer, I found that I was taking the first developer (instead of the first component of the colour developer) in my hands. In that particular case, I just prepared the first developer, put it in the colour-developer flask, went back to the first developer (which only contained the first component of the colour developer) add the second component, and so I ended up with a normal first developer, and a slightly diluted colour developer (170 ml of final solution instead of 140 ml), the colour developer in flask marked "1" and the first developer in flask marked "3". Colour developer goes to completion, so I adopted a 10' bath instead of the canonical 6' bath, and it all seems to have worked very well.

But in any case I could have discarded the colour developer and re-mixed it again, it was only 140 ml of final solution, nothing to cry upon.