Eh, while a single battery may be more expensive. You only need 1 battery for the car for an entire race. You don't need 2 or more sets of batteries.
ROAR can do the same approval system that they currently use for NiMH and NiCD cells. They approve the companies and brands that meet necessary safety regulations for each cell that is submitted to them for approval. In other words, old cells from the past, do not necessarily have to be approved.
Paul