There is no Control between TECO of PM Order & Completion Confirmation.
Even with "No Confirmation" or "Partial Conformation" of operations, TECO is possible in standard.
You can use either Development by checking CNF or PCNF statuses (if you don't want to give control to any user) to restrict the TECO.
User exit will be Either IWO10009 PM Order: Customer Check for 'Save' Event or IWO10004 Maintenance order: Customer check for order completion
If you want to keep control with user, you can create "User Statuses" accordingly to allow / disallow the TECO of the order. Initial status would be "Confirmation Not done. TECO Not allowed" which will forbid the TECO of PM Order through Business Transaction.
User has to set "Confirmations done. TECO allowed" manually in PM Order.