To our young people in IT: Watch "Office Space"! It is still hilarious and you may find it easier to recognize some more or less subtle repferences (for example to red staplers, tps reports etc.). Also, it features some solid rap songs by Scarface, Geto Boys etc..
Edit: Here is the printer scene https://www.youtube.com/watch?v=N9wsjroVlu8
PC_LOAD_A4 just isn't confusing enough.
LOAD_A4_PAPER or INSERT_A4_PAPER etc also fit within the limited length of the message.
I have done a stint of helpdesk work and can’t see that this would be too catastrophic.
Yes, it'd cause the person to check every tray, but in my experience they do anyway.
The "LETTER" part was meaningful, because it meant the "LETTER" size, as opposed to some other size. "PC LOAD LEGAL", for example, is another message it displays.
Probably they could have just omitted it entirely and let the use work out which paper source was empty. After all, since not everyone knew what the message many at all, that's what they did anyway!