[Zubersoft]

MobileSheets, by default, copies files to its application storage directory. If you open a file in an email, MobileSheets has to copy it somewhere. If you want to specify a location on an external SD, you need to go into the settings, then go to Set Removable Storage Location, and pick a folder on that SD card. Then on the song editor screen, you need to tap the hammer & wrench icon and change the copy to location to "Removable Storage".

Things are a little bit simpler in MobileSheetsPro, and there is an option to switch the entire storage location over to a different folder, so you may want to wait for MS Pro before trying to fix files that have already been copied.

Mike