Wow -- I wonder why I haven't come across this fact before? Seems like it would be highly relevant in any discussion of "is this gold coin legit, it's out of weight tolerance". What year(s) did the shift happen?
I'll see what I can find out, but since they were very strict with gold the light to heavy range probably wasn't very wide.
This is a pretty good conversation about this topic. I wasn't expecting it. I've learned some things.