I don't think that is the case either.
I've only had one subpicture stream checked off (English). For instance, the one in front of me only has one subpicture stream.
I would be just as happy with it in a separate file, but most of the times I tried that, it froze up on me.
I'm trying separate file on something right now, but it takes about 2 hours on that computer, so we'll see.
Thanks for the help tho