I'm not eminent, far from it, but I was basing the comment on the idea that when acidic ammonia salt fixers go alkaline, they start to smell. The acid of the stop bath neutralizes the developer, which tends to be alkaline (except for things like coffee & ascorbic acid developers), then goes further to make the film acidic. Then the acidic film and clinging drops go into an acidic fixer and all is well.
Originally Posted by Ian Grant
That's my understanding of a desirable chemistry, but probably I'm missing something if you recommend an acid stop bath with an alkaline fixer.