I just noticed this thread (8 years later!).
Proctor-silex toasters, and ONLY Proctor-silex toasters (from what I’ve seen), have a temperature sensor that sits right up next to the bread. Instead of sensing the temperature of the toaster’s innards, it senses the temperature of the bread you’re toasting.
This sensor is only present in one slot, however. That’s why on Proctor-silex toasters you’ll see one of the slots labelled “-> One slice ->”.
I’ve found this to be an invaluable feature. If my toast isn’t quite done, I can put it back in, and push the lever back down, and it will only toast for a TINY LITTLE BIT of time. If I put a fresh piece of bread in, it will toast for the full duration. All without having to tweak the light/dark knob at all.
P.S. – I hope Sattua managed to get her toaster working in the intervening 8 years! I’d hate to think that she was a woman without toast for that long.