Jon, thank you for responding. The reason why the copyright was renewed in 1937 is because if it had not been renewed in 1937, the copyright would have run out in 1937. However, that this event took place fully three quarters of a century ago is certainly not irrelevant.

Regarding George Harrison, the first time that I heard the song "My Sweet Lord" on the radio, I immedately recognized the melody as being that of "He's So Fine", and I knew that the original composer was either already paid, or else that he would probanly bring a legal case to bear on the matter.

Somewhere on the internet is a full explanation which is written by a copyright lawyer showing just why it is that 1922/1923 is the cutoff date for copyrights, depending upon from which side of the line we are approaching. I used to have that page bookmarked, but I will look for it again.