Genioplasty - why would a doctor move a chin down diagonally and not forward? (Photo)

Why woul a doctor move a chin down diagonally and not forward? I got a sliding genioplasty and a revision but my doctor moves the bome diagonally and not fowrd/backward or up and down staight. Now I am post op my revision and I still have the Sarah Jessica Parker chin. Vertically and horizonatally my face is so long and the chin looks added to my face and not like it's part of my face.