If you have Reservation for 10 qty & you have only 3 in stock. For remaining 7 qty (open reservation), by running MRP, PR has been generated.
As you have only 3 qty in stock, you could have issued only 3 for that PM order. So there will be a difference between committed qty & withdrawal qty (unless qty in PM order has been changed to 3 as there is no stock).
You can control the TECO by checking the difference between Committed & withdrawal qty. Also, sometimes, it may require to close the order (complete the temporarily) as that specific spare part may not be available in the near future. So you have to give authorization only to specific users to edit / change the qty.
This can be achieved by having combination of User Status & some development. Maintain User Status as Components modifiable & Components non-modifiable. Give the User Status authorization only to some responsible person. If he changes that to component modifiable, then you can edit the planned qty to withdrawal qty & anybody can complete the order.
If he doesn't change the qty, then using development, TECO can be restricted.
