You're being cast for your acting ability. It's not based on the way your body functions. If you're playing a lead in a movie, it's for that character and they'll tailor it to you. In a dance company, you have to fit in a definite mold.
This does make me very very careful, particularly in the second draft, to get it right, because you do feel that somebody in the future who may be extremely important for everybody, is going to have me behind them, and this is a responsibility, a huge one.