When there is more than 1 to choose from which one do you pick. Sometimes there is a 6ch stream and 2ch (i always pick the 6 ch one) is this right?

What about when they are like this :

Stream[002] X=[[0x80] Audio English AC3(2Ch) 48kHz ] [] [] [] []
Stream[003] X=[[0x81] Audio English AC3(2Ch) 48kHz ] [] [] [] []

They both look the same, so does it matter and why are there 2?

Thanks 8)