"So if I'm thinking right, the 12 degrees I have it set at now, is actually 18 degrees. Would that make sense?"

You're confusing camshaft degrees with ignition timing degrees. The amount the cam is advanced or retarded in relation to the crank has to do with the valve timing (when the intake and exhaust valves open in relation to the crank), not with ignition timing (which is when the plug fires in relation to the position of the crankshaft).