Bifunctional enzyme involved in flavonoid metabolism. a (2R,3S,4S)-leucoanthocyanidin + NADP(+) = a (2R,3R)-dihydroflavonol + H(+) + NADPH (2S)-flavan-4-ol + NADP(+) = (2S)-flavanone + H(+) + NADPH Pigment biosynthesis; anthocyanin biosynthesis. By light. Belongs to the NAD(P)-dependent epimerase/dehydratase family. Dihydroflavonol-4-reductase subfamily.