Good question and a technical one to answer, but I'll do my best. 11-OXO aka 11-sterone is a selective inhibitor of 11b-hydroxysteroid dehydrogenase type I reductase. 11b-hydroxysteroid dehydrogenase type I reductase turns cortisone to cortisol and by inhibiting this process, you therefore, reduce cortisol.
Suppress C contains Androst-5-ene-3b, 7b, 17b-triol. Androst-5-ene-3b, 7b, 17b-triol is a metabolite of DHEA and DHEA is a cortisol anatogonist.
11-OXO inhibits cortisone to be converted to cortisol.
Suppress C promotes DHEA and DHEA decreases cortisol.
I hope that was clear and most importabtly accurate. This is my understanding in contrasting the two.