Value of two second class stamps on letter (old style, pre-bar code)

[Joclemence]

Hi everyone,
Pre-August 2023, with the old style regular stamps (the stamps that expired in late July), how did the sorting machines and staff treat a letter with two NVI second class stamps on it? Did the machine read it as sending first class because of the combined value of the stamps, or just as second class mail? Would the machines have read it as two phosphor bands, and therefore sent as first class? How about if the staff sorted it? I’ve searched the forum but can’t find an answer.

[BenacreNick]

I'm not too sure about the CFC machines Jo, but if manually sorted with 2x 2nd class stamps then it would have been sorted as a 1st class item for sure.

[Joclemence]

Thanks Nick, good to know that the sorting staff would treat it as first class. Still wondering about the machines though.