Replying to Different companies measuring ski sizes differently?

So I was talking with a friend about ski lengths the other day and that got me thinking about how different companies measure the lengths of their skis. I've heard some stuff about companies measuring their skis with the curveratures in the ski so that maybe a 185cm with a lots of rocker could actually be only like 180cm tall. So is if there is a standard way that companies measure ski lengths? Or do some companies use one way and others use the other way? If so which companies use which ways? Sorry if it's a stupid question. Just something I wanted to know for some reason.