After eight weeks of waiting I received my results.
The maximum possible score is 400; the minimum to pass is 320. General Considerations (maximum = 100): 90 Documentation (maximum = 70): 69 O-O Design (maximum = 30): 30 GUI (maximum = 40): 29 Locking (maximum = 80): 44 Data store (maximum = 40): 40 Network server (maximum = 40): 40
For locking I'm really not sure. I know there exist blocking scenario when the same client would lock record twice, but I described it in choices and I didn't want to break the must requirements - there was something like the thread must block on already locked record...
For gui I make nice design with extensible framework, but without eye candies and comboboxes etc.