diff --git a/multiple-cursors.el b/multiple-cursors.el
index 6cad9e0..cd08fc3 100644
--- a/multiple-cursors.el
+++ b/multiple-cursors.el
@@ -223,10 +223,8 @@ mark-multiple if point and mark is on different columns."
     (error "Mark a set of lines first."))
   (mc/remove-additional-cursors)
   (let* ((point-line (line-number-at-pos))
-         (mark-line (save-excursion (exchange-point-and-mark) (line-number-at-pos)))
-         (num-cursors (abs (- point-line mark-line)))
+         (mark-line (progn (exchange-point-and-mark) (line-number-at-pos)))
          (navigation-func (if (< point-line mark-line) 'previous-line 'next-line)))
-    (exchange-point-and-mark)
     (deactivate-mark)
     (while (not (eq (line-number-at-pos) point-line))
       (mc/add-cursor-at-point)