We play this, sometime I should listen to the original.. The B D E riff fits with what the guitar players play. and just seemed instinctive to drive the song along. Sometimes I follow the the descending chord changes, other times I keep the BDE riff going over them. An interesting error jazz variation (related to my ability with the 5 string) occurred last week. I followed the descending chords a 5th lower. Not unreasonable , guitarists did not complain.