Do you mean the quote from JayArgonaut regarding Lando's line?
IME that's describing a difference between the THX mix vs. its predecessors,
not a difference between 1478-80 & 1478-85.

So I'd forgotten about the UK PAL 1478-80, which shares the same catalog number with it's domestic counterpart. That confuses the discussion.

The NTSC 1478-80 pressed by Pioneer in Carson, California has copyright (c)1986 (not '85) and it Shirley contains a digital track. I'm holding it now.
I've got a hunch that's the one d_j captured too.

As for the actual contents of the PAL 1478-80, that's still up in the air it seems...