Recent research indicates that black holes can grow based on the expansion of the universe and not just through accretion and mergers. Two different models independently predicted that finding. One model, describing the relevant massive star remnants as "generic objects of dark energy", rejects the traditional view of black holes while hypothesizing that dark energy causes the cosmologically coupled growth of these objects. The other model, based on the probabilistic spacetime theory, indicates the growth of black holes is based on the same spacetime mechanism underlying all universal expansion, and does so while leaving the traditional black hole conceptualization essentially intact. The fact these two models predicted this observational finding but did so from different perspectives suggests more can be learned by further study of their differences. This paper explores similarities and differences in the two models' explanations for massive star remnants' growth, concluding with suggestions for research testing their relative veracity. An exploration of the relative utility and parsimony of the two models is also described.