Catalysis of the reaction: H+ + (22S)-22-hydroxycampest-4-en-3-one + NADPH + O2 = (22R,23R)-22,23-dihydroxy-campest-4-en-3-one + NADP + H2O.
(22S)-22-hydroxy-campest-4-en-3-one C-23 hydroxylase activity