This is the final part of a three-part paper. In the first part, it was proposed that a notion of phenomenon type could be relevant to tackle some crucial issues about incommensurability. Then, part II had a focus on some remaining problems associated with scientific realism and the possibility of scientific progress. In this part, some ways to solve them are offered, without abandoning the classical features of incommensurability. This can be done by showing that two rival theories may refer to the same phenomenon type even if their ontologies are incompatible and assuming at the same time a non-naive, moderate scientific realism.