Is there any other part of your application that will be able to unambigously detect/determine this time?

Yes, but it is a bit inconvenient (that part would first have to identify the host where the respective instance had been executed, and while this is technically possible, it is a bit "against the priciples" of the dispatching tools, which adhere the principle that the manager should not care where its instances are executed). But if necessary, it *can* be done, and this would have been my "plan B" if the locking policy would not have worked out.

Fortunately, after the precious comment of JavaFan, I think my revised design is sound and will do what I expected (I still need to test it, of course).