I still think buffet catering and a la carte catering are just about the same. I helped to cater a wedding with a friend of mine. My friend was insisting it was buffet style, and the mother of the bride insisted it was a la carte.
The bride even put a la carte on her invitations. I just do not get it--it is pretty much the same thing. In both styles of serving, you pick out what food you want to eat. Both types of serving usually involve paying a flat price to get anything you want, except this time the bride's parents had paid for the meal.