I am writing this for a friend of mine.
He has been skiing for 2 years and progressing. He was borrowing a friends equipment and recently bought his own from a reputable ski shop. The boot fit is great and the skis seem to be perfect. He did very well last year but his first time out this year He had a lot of trouble controlling the ski. His butt was sticking out and he was bent over and he was told his boots are to stiff. To confirm the teacher had him unbuckle the top buckle and he immediately was able to ski in control. Does boot flex have that much to do with skiing and how to tell if the boots are to stiff?