We propose an algorithm, CBM-Gen+, to refine case bases for hierarchical and incomplete domains. In these domains, the case bases are the main source of domain information because of the absence of a complete domain theory. CBM-Gen+ revises the existing cases when a new solution is captured. The main purpose of this revision is to reduce inconsistencies in the cases. We will prove that CBM-Gen+ is sound relative to the captured solutions. We also perform experiments showing that CBM-Gen+ is on average at least as efficient as a previous approach for constructing case bases for hierarchical domains.