Dryer Heat
Bob,
Those heat choices on the dryer were a carry-over from the earlier all-electric days. Both heating elements were the same wattage, so with one coil you got "low" heat, with both coild on you got "hi" heat, with neither on you got air. Later they varied the wattages of the two coils so you could get "low", "medium" and "hi" in addition to air. Even when the electric dryers were limited to 2 heats, they could have configured the gas models differently and offered another heat option, but that would have required unique consoles (not smart).
Lawrence