Here are the images of three different holograms from $10 Frontier-Polymer Series Notes. Annotations are explained below and you can get to higher resolution image by clicking the thumbnail:
A- Clearnace of "O" above hair
B- Distance of Hair from hologram edge
C - Black dot on nose
D - Clearance of "0" at ear lobe
E - Location of "1" at collar tie
I have classified the three variations as 1, 2a and 2b. The variation 1 is similar to the one that is shown on the BoC design. This is the most common. Type 2a is not as common and Type 2b is the least common.
A keen observer will notice that essentially there has been a shift between the portrait and the text. However the dot on the nose cannot be explained by the shift
Similar variations are seen in $20 and $5.
Has anyone found something similar or different?
I believe that similar variations have been noted with holograms on stamps.