(S)-tetrahydrodehydrodiconiferyl alcohol + NADP(+) => (2R,3S)-dihydrodehydrodiconiferyl alcohol + NADPH + H(+)
(s)-tetrahydrodehydrodiconiferyl alcohol + nadp(+) => (2r,3s)-dihydrodehydrodiconiferyl alcohol + nadph + h(+)