I think you've got this already, some way or another (i don't havetime to dig into it at the moment - it's either the Worskpace or some project setting. What is really needed is separate translators for export and import. Now, settings used for one may not be applicable to the other. Too confusing.
I think that Thomas Holm has right. I set up my dwg translator to work with my default template archicad file (layers, lines colors etc) and it is ok. But what is happening when you get an archicad file from someone else who has different layers names, different lines etc? You have to spent another "half day" to create another dwg translator. It is not so big problem when you co-operate with one or two persons, but try to imagine what will be if you get 20 different files and for each one you have to prepare translator.