That's controlled by at least 3 parameters: "crotch drop", "crotch seam bend" and "crotch seam angle". I guess breast fit is a complex enough change that doing

That's controlled by at least 3 parameters: "crotch drop", "crotch seam bend" and "crotch seam angle". I guess breast fit is a complex enough change that doing it with parameters wasn't feasible, so they had to fork the designs.