Is there any way to see which saver seats are available for pre-assignment (if any) before you purchase? When doing a flight search, the "S" seats don't show up like the premium and elite seats when you click on the seat map. Is there a standard set of rows for each aircraft...last 3? last 4? I booked saver seats on a Q400 flight and although they were all toward the back (near the door), there were plenty available for pre-selection.