[Zubersoft]

Let's talk about how you set up the batch import. If you selected "piano_music" as the folder to batch import, and then checked the option to "Scan all subdirectories for files", it shouldn't have used 2-Pianos as the composer name. It should have used Rachmaninoff (so long as your metadata format string was just %COMPOSERS%). However if you just selected "Rachmaninoff" as the folder to import, then it would use 2-Pianos as the composer name. If you selected piano_music as the folder, but it still used 2-pianos as the composers name, let me know, as that would be a bug and I will investigate it immediately. 

Thanks,
Mike