Here's more interesting info:

My curiousity got the better of me, and I opened up a box containing a new Trinity D3.5 that I'm getting for Christmas. (Yes, I am a bad boy.) My testing of the D3.5 revealed that the 0 degree setting on it is actually 30 degrees advance! I did a quick search here on RCTech, and some posts indicate that this has been confirmed by Trinity. I could find no information on the Trinity web site, and nothing in the instructions for the motor mentions this.

So it turns out that different manufacturers do use a different reference point for the labeling for the timing adjustment. I simply named the wrong manufacturer!

It makes me wonder if whoever did the labeling for the D3.5 used a Novak ESC and the same procedure as I did to determine the endbell position for 0 degrees advance, and arrived at the same incorrect result.

EDIT: I just checked a Tekin Redline motor. The 0 degree marking on the Redline is also actually 30 degrees advanced! The lesson is: trust no one. Measure timing yourself to find the actual value.