When I got a new Rowenta I wanted to know what they highest temperature was. So I called them. Apparently, they don't make their irons to certain temps at the settings. Instead, they could have a range of temperatures. So each iron could be of a different temperature at any setting. I needed a temperature of 350º but the iron only got to 340º at the highest setting. I don't know if this is true of other brands of irons, but it is possible that you have an iron that gets a lot hotter than other people.
I don't know exactly what my husband measured the temperature for me, but he used a thermacouple and I put my iron on top of it.