If you are talking about phonological categories, then you are almost certainly correct. However, somewhere between choosing to produce certain phonemes and the

If you are talking about phonological categories, then you are almost certainly correct. However, somewhere between choosing to produce certain phonemes and the actual sounds you produce, there's some process (maybe just the physics of your vocal tract) that gives rise to tons of variation in what linguistically is a single phonological category. IPA doesn't capture that. Of course, IPA does capture unstable vs constable.