Involved in reduction steps of the biosynthesis of plant campesterol-derivative steroids, ending to castasterone (CS) but missing brassinolide (BL) (PubMed:32146811). Catalyzes the conversion of (22S,24R)-22-hydroxy-5alpha-ergostan-3-one (22-hydroxy-campesta-3-one, 22-OH-3-one) to 3-dehydro-6-deoxoteasterone (6-deoxo3DT, 6-deoxo-3-DHT), 3-epi-6-deoxocathasterone (3-epi-6-deoxoCT) to 6-deoxotyphasterol (6-deoxoTY) and of 6-deoxocathasterone (6-deoxoCT) to 6-deoxoteasterone (6-deoxoTE) (PubMed:32146811). 3-epi-6-deoxocathasterone + O2 + reduced [NADPH--hemoprotein reductase] = 6-deoxotyphasterol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (22S,24R)-22-hydroxy-5alpha-ergostan-3-one + O2 + reduced [NADPH--hemoprotein reductase] = 3-dehydro-6-deoxoteasterone + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] 6-deoxycathasterone + O2 + reduced [NADPH--hemoprotein reductase] = 6-deoxoteasterone + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Plant hormone biosynthesis; brassinosteroid biosynthesis. Belongs to the cytochrome P450 family.