I'm just saying that one specific setting named "MergeProfilesIntoPolyline" only seems to be available when using the DataIO.WriteDataToFile method of exporting to DXF, but does not appear to be available when using the TranslatorAddIn.SaveCopyAs method of exporting to DXF.
However, I opened my INI file again this morning, to have another look, and I do see an option/setting within it called "GROUP GEOMETRY", which is currently set "=No". Maybe this is that same setting, but with a different name. Merging profiles into a polyline is pretty much just 'grouping', since all the individual entities retain their sizes, shapes, orientations, and such. The only time I think I ever see that setting being available when exporting anything to DXF manually, is when I have a true sheet metal part open, and it has a Flat Pattern, and I am in flat pattern edit mode, then I right-click on the Flat Pattern node, choose 'Save Copy As' from that right-click menu, specify the path and file name, then click the Save button, then a dialog shows. In that dialog, there three tabs (General, Layer, & Geometry) for specifying all the different types of settings. On the tab named Geometry, within a sub-area labeled '2d Geometry', is a checkbox option named "Merge Profiles into Polyline". If I go through that process again, manually, turn that option on, and save that configuration to a new INI file in the process. Then open that new INI file again afterwards, I can see that this option named "GROUP GEOMETRY" is now set to "=Yes", instead of "=No". So, this must be the same setting, just with a different name within the INI file. So, the only way to set those options is through the 'manual' export process, and saving those settings changes to an INI file. Then, if you are using the TranslatorAddIn.SaveCopyAs method, you would specify that INI file as what options to use.
Wesley Crihfield

(Not an Autodesk Employee)