Paul - you hit the nail right on the head. It's interesting, isn't it, that some tunes can undergo a sea change out there in the wild, away from the dots, while others - such as the aforementioned "Ashokan Farwell" and "Da Slockit Leet" seem to spread around with very little melodic change (as far as I can tell). Is this because the melody lines are so strong as to be invincible, I wonder? :-)