No, there is a point at which all the propane is burned. It's called the stochiometric (sp) ratio. Adding propane beyond that point will result in a rich mixture and a cooler flame. Too little propane and the flame goes out.
In a gasoline engine, the stochiometric ratio works out to 14.7 parts oxygen (NOT AIR) to one part fuel.
Air is 21% oxygen. Oxygen is 100% oxygen. More O2 means more fuel can be burned and more heat can be generated.
Now do you get it?
I don't know how you derived that. Air is air- a mix of 21% oxygen and
78% nitrogen (and some trace gases). When air is mixed with a fuel and burned, more than the O2 is consumed- depending on the fuel and combustion temp, the end gases may include carbon monoxide, carbon dioxide and various nitrogen oxides. The torch can't magically seperate the O2 out.-Carl