Marc: As to the problem where line annotation is not removed when adding a curve. This sounds like an oddity of the workflow. I'm speculating some since I haven't seen this demonstrated, but I suspect what is happening is: The line is created and annotated. you add a curve which updates the complex but does not update the status of the original line in GPK file. Thus, although you have a single complex in dgn, the GPK has a line and also a complex, oth of which are annotated.
The obvious fix of course, is simply clean up the extra annotation. For additional guidance about possible better workflows or to investigate possible bugs, I'd suggest placing a support call.