This might take the prize for dumb questions but...
I use one shot chemistry in my processor when developing film, so is a stop bath, or a water stop neccesary or even desireable? IIRC the reason for a stop bath is to prevent the fixer from going south on you from being contaminated by residual developer, but as I'm not reusing the fixer since the processor only requires a small amount of chemicals I prefer to use the "one shot" approach rather than risk exhausting the fixer, so....? or is the residual developer enough to have an effect on the fixer and that would be all the more reason to use a stop?