No, it shouldn't but it is. Welcome to the sometimes nightmare known as COM Interop. I have written extensively on this area starting about a year ago thinking the whole darn thing was flawed evolving to a state of acceptance that its the best that could be done. Check them out.
I just did. it's nice to get the feeling that you are not the only one who feels a bit helpless at the sight of these COM interop flaws and misleadings. I do wonder whether there are any news from MSFT about revising/changin this whole approach in the upcoming versions... surly this can't go on.
I think a lot of developers and shops that bought into this whole interop being "easy" will try, burn and maybe even go back to their old VB/Other COM apps, since rwriting their whole structure would just be too much to handle in one big swoop.