xschris,
The timing is set to 10 deg BTDC at idle (1200 RPM). The PAMCO E-Advancer then adds 30 degrees at full advance for a total of 10 + 30 = 40 Deg BTDC. Advance means Before Top Dead Center (BTDC). In advance of. Before. I have no idea where you got 10 deg ATDC. The curve in the above post is the advance added by the E-Advancer, so it is in addition to any fixed advance that there is at idle, and that is supposed to be 10 deg BTDC. The curve only shows the advance added by the E-Advancer, not the total advance. You have to add 10 degrees to any point on the curve to get the total advance.
Think in terms of the mechanical advancer. Before the springs expand, the timing is 10 degrees BTDC, so as the springs expand, they add to that initial 10 degrees.