Hi,
The lock in cost center is against posting, so there will be no control as that level for the creation of a work order with a locked cost center.
Further more the locks are specific to nature of posting. In your case it looks like your cost center is not locked against secondary posting. You can check that in the cost center master data, tab control.
Resp. cost center in a work order comes from the main work center. In your master data maintenance processes you should use validity date to control these assignments. You should also put the valid cost center you want to use to charge labour hours in the main work center.
Regards
Ali