[DCP-o-matic] videos is copied or hardlinked?

I remember something about the mxf file being hardlinked and not copied from the "video" directory to the final DCP directory, or moved as the sound mxf. But OSX keeps giving the size of the full project directory as about double the size of the DCP. And had many times the error when trying to make the DCP sirectly in the usb key where I intended to deliver the DCP, so just slightly bigger than the expected size, not double. If the files are actually copied, an option to specify a different location for the result DCP will be great in many many cases. Thanks! Manuel AC