TurboCAD 5 seemed to be "crazy" with saving files, constantly prompting about overwriting a file even though it had been the actual document that was opened.
After making edits and habitually doing Command-S, it would pop up the file dialog and inform me that the file exists, rather than just save to it like expected. Sometimes I ended up with stacked extensions on filenames too. All the drawings are done in thousands/mil, three digit decimal.
For exporting to lasercutting, that part has always worked. For my workflow, I would select the segments I wanted to export, use the export command, select DXF, Selection Only, DOS/Windows file format, and 1" = 1 Unit.
The pre-processing software and the laser cutter are on Windows 98 and DOS 6, respectively, (yes, old machine), the pre-processing is done using a Virtual Machine (VMWare) on the same Mac and the GCode that is created from that exported DXF is saved to a network share that the cutting machine has access to.
In closing, the import/export for DXF have never given me any issues, and with Version 7 it seems to work even better than ever.