Its because of the NAZIS !!
during the second world war the only way to reasonably get coal to London was by boat from Newcastle. By 1941 Hitlers u-boats were sinking so many coal ships that coal was in short supply. However bread being made in the surrounding home counties was plentiful. Therefore all toasters were overhauled as part of the war effort, so that blitzed Londoners could cook their bread into charcoal substitutes to stay warm.

After the war the older generation , still living with rationing and shortages would only buy toasters with settings high enough to make their own coal. This continued the practice of having too high settings on the toasters as it was now tradition. Meany social historians also believe that that toast-coal was the major cause of the failure of the miners strike in the 80's .

Toaster manufactures , in their cut throat world, are forced now to include extra numbers or risk loosing out on the lucrative pensioner/survivalist market as apparently these people really like toast.
( willenium Fist bump for verification, Sat 5 Jan 2008, 13:41, Reply)