I don't agree, and there's not enough data at your link to check it out. Yes, normally split Indies broke for the Dems in 2006. But how many of those Independents were Republicans two years prior? Without a measure of that, I'd really like to look at turnout data (paging Michael Barone) of strong GOP areas, swing districts, etc.
Well, I don’t have any additional data either. I do remember that many of those races were razor-thin close, but nearly all of them broke the Democrats’ way.
As for how many 2006 Independents were Republicans in 2004, I don’t know. As you correctly point out, my handy dandy chart doesn’t give me that information.
Michael Barone is the Sarah Palin of political analysts. :)