Larry, I went back and re-read Kennett, 1978 on the Belgian proof marks. He mentions the various changes in the proof agreements (Brussels Convention). Reading his various articles, from what I can gather there are 2 levels. The Convention and then minor agreements between Conventions. Belgium adopted the 1924 changes rather quickly while others put it off until 1925.
I am sure since the EU that "fudge factor" has changed. While the English follow CIP, they may not be "ruled" by it since they are not part of the EU in all matters.
Hopefully, some of our European based members will chime in.
Pete
