But to boot, I think I kinda misunderstood quadibloc's comment on the matter.
What I meant was that all the different ISO keyboards use the same scan codes for corresponding keys.
So an AZERTY ISO keyboard and a QWERTY ISO keyboard don't have different scan codes; the change from AZERTY to QWERTY doesn't happen at the keyboard level. That was what I had said.
An ANSI keyboard is missing the <> key. It doesn't add its scan code to that of the shift key which now covers the space where the <> key was, nor did I intend to imply such a thing.
The Group 1 and Group 2 scan codes of the |\ key on the ANSI keyboard are the same as those of the key to the immediate left of the lower half of the ENTER key on an ISO keyboard. (The Group 3 scan code, not normally used in Windows or DOS, is different, however.)
Except for those two differences, the <> key being missing, and the |\ key being essentially moved, the scan codes of an ANSI keyboard and an ISO keyboard are also identical.