My sincere apologies to all. Yes, both methods work, exactly as they were presented earlier. The approach using App.config / Application.config works and the approach using (+B-F-N) in the Command Line Arguments of the Debug tab works. I have tested both approaches with both native and managed, and they all work. In managed, I have tested with console projects and win forms projects, and they all work.
So what was I doing wrong earlier? Very simple (now that I see it). In our environment, in practically all cases, we have the program that we are working on, which is a DLL, whether it is a managed or native. So, we typically have a solution that has the DLL program in question as one project along with another project which has a simple program that starts first and calls or invokes the DLL program, passing whatever needs to be passed (user ID, etc.) Essentially, this simple caller / invoker program simulates the main menu etc. of the production application. Well, regardless of the approach used, the run-time COBSW switch settings need to be established in the start-up CALLER / INVOKER program, not in the called/invoked DLL program. When I finally realized this and tried the approaches at the right place, everything worked as advertised. Thanks and sorry about my earlier confusion.