Nobility is inherited in my book whether a character has high or low SOC. An Admiral can get high SOC, but still not belong to any nobility. The moment a player rolls up a high SOC, he or she can decide if in fact their character is a member of some dynasty (and all that entails) or not. The reverse can also happen. A character is decided to be a member of some dynasty, but the player has rolled a SOC of 5 for them. The character is still nobility. Just a bad seed, black sheep, bastard, doesn't know, orphaned, whatever.