Measuring Wrap Angle Revisited

[icarectr]

So, I see numerous posts about how to measure wrap angle, but have a question about which of two ways is the correct way to do it:

Some methods advise measuring along the angle/line from the CENTER of the bridge to the temporal eyewire groove, and others say you should measure from the NASAL EYEWIRE GROOVE to the temporal eyewire groove.

I have noticed that the two variations in measuring do yield results differing by 2-3 degrees.

So which method is correct/accurate?

[Tallboy]

I line up the eyewire of the left lens so both the nasal and temporal edges are perpindicular to the base line, then I measure the angle line passing through opposite temporal edge in the right eye.