[Defmzk]

Код:

for i:=0 to Series1.Count-1 do
  begin
    With Series1.Marks.Positions.Position[i] do
    Begin
      Custom:=True;
      LeftTop.Y := LeftTop.Y - 35;
      LeftTop.X := LeftTop.X - 35;
    end;
  end;
  Series1.Marks.Arrow.Visible:=false;
  Series1.Repaint;

может так получится