The -6 refers to the difference between strongly approve and strongly disapprove. Most of these folks are probably in the somewhat disapprove which is not picked up in the daily tracking poll that you are referring to.
That could be. I’m watching the poll shift from double digits to single, and back, and it seems that if more people are jumping off the bandwagon the number should be moving negative much more quickly. But you’re right - it’s probably the tepid disapproval for the independents now.