I came across this interesting set of stock certificates. Both issued to the same person and sold (transferred) the same day, Jan 11th, 1944.
One has NY Stock Transfer Stamps, a series 1942 1c Red Doc, (R336) and two 1943 Green 10c Stock Transfer Stamps (RD144) and a RD142 4c Green Stock Transfer stamp.

The next does not have a documentary stamp - Why would one have one, and one did not ? Same type of transaction, exact same person and exact same date. The expected NY State Stock Transfer stamps, and a Green RD148 50c Stock Transfer stamp.
No documentary stamp.

Any ideas why ? What are the rules for usage? My current assumption is they were missing a Green Stock Transfer 1c stamp so used an old Red Documentary (the 50 shares is exactly double the 25 shares value)

