At first, I thought you were nuts, Speakerguy, because like you, I always use the standard machinists' table. But you are correct. The diameter advances by 0.0130 between steps and 0.0160 between double steps. I'm sure sizes are smaller than #0 simply because the teensy screws used in watches and meter movements are smaller than that. But most modern charts stop at #0. Number sizes move in single units until you hit #6 and after than they move by 2. So the standard charts list 0.1,2,3,4,5,6,8,10,12 and then move on the using the actual dimension, usually in fractions of an inch. Once you hit the fractional major diameters, they increment by 0.0625 (1/16 inch), of course.
Dean