The Dulac Question

Not too long ago I wrote about the Marianne de Dulac stamp, which has either one or two engravers attributed to its design: Edmond Dulac and Leonard Vincent Phillips. John from Australia then contacted me and he sent me this gif which is absolutely fantastic as it makes it so much easier to compare the two versions. Here it is:


He wrote he thought he could distinguish the following differences:

- The circles under the laurel leaves (if that's what they are) are a different shape. One is more rounded and the other more oval.
- The cross is fatter in one. 
- The F in RF seems different, I think in the lower of the two horizontal strokes.
- The lines on the back of the neck seem different.
- While the cross-hatching is almost identical there are small variations.
Can you as well? I believe the circles and the cross varieties are the most obvious. Most intriguing! Question remains of course: What happened and why?

:-)
Adrian