"Switches off while you are unconscious" is a -10% Accessibility (see
this post).
DR 10 (Force field, +20%) [60]:
You are always covered with aura of protection. You enjoy your DR even when a foe makes a surprise attack on you while you are asleep, but you'll have trouble having medicine injected, taking surgery, etc.
DR 10 (Force field, +20%; Switchable, +10%; Accessibility, Switches off while you are unconscious, -10%) [60]:
You are usually covered with aura of protection, but it conks out when you fall unconscious.
DR 10 (Force field, +20%; Switchable, +10%) [65]:
You are covered with aura of protection, and you are allowed a choice to be covered or not to be covered.