AG4Life - 3:40 pm on Sep 10, 2012 (gmt 0)
Thanks for the explanations, it all makes sense now.
I wonder why these 404s are showing up again though, 28 month after I made the changes that led to the creation of these 404s. I'm fairly sure most of them have already been processed in the past by Google (ie. they've shown up in WMT before, if I can remember, not too long after I made these changes). Maybe just Google being extra thorough/re-checking just to be sure?