What I mean is if you take the Skull & Roses version and compare it to, let's say, 1977, the whole tempo is turned inside out. As I remember, it was like the song could be considered as starting on the C chord when you're right in the middle of the song, rather than being based from the G > C back and forth repetition. Being a player, when I'd hear it I'd think what is this all about, what happened to this song. (Sort of like the early version of Playin' versus the Ace version, or the early versions of Dancin' versus the descending 7ths version much later on.) The song had completely morphed from the lead lines of Jerry, too. His style of play had become much more opened up, he had become a really good guitarist with the ability to do whatever he wanted. When Bertha first came out it was really close to the Skull & Roses version, staightforward rhythm with lyrics, you would recognize aspects of the version when they would play. But in later years, each live version was anew and unique, very much morphed.
Then came the BAM, because it was like a guitar pyrotech technique that, with all of the instruments doing it at once, you could actually feel a wave of sound hit you. The Dead liked that sort of thing. Sort of like the record-skip effect that they could make happen in Cassidy, where time would stand still for an instant.