fix obj error in assignment statistics - fixes #581
fix obj error in assignment statistics - fixes #581

jordonwii/ok,Cal-CS-61A-Staff/ok,Cal-CS-61A-Staff/ok,jordonwii/ok,Cal-CS-61A-Staff/ok,Cal-CS-61A-Staff/ok,jordonwii/ok,jordonwii/ok,Cal-CS-61A-Staff/ok