I upgraded from Panasonic AE900 1 month ago. It is ceiling mounted. After 150 hours It has a problem possibly dust particles. Attached pictures are of my HTPC black desktop in natural mode. There is also some MC. I will return it to the store which has a 3 month return policy. I just feel sorry for other owners that have to deal with repair center. And after that it will get particles again. I hope I am wrong and dust can be prevented with placement of extra filters on unprotected air openings at repair center or by owners.
Some may argue that it is only noticable on dark screen but if you watch a letterbox material and the artifacts are at the peripherial locations it can be annoying.

They look like dust blobs to me, but more obvious than I've ever seen. Too bad because your focus and convergence look much better than my AE2000. I have blue off by a pixel and a half across the entire screen and green is off by a pixel only on the right half of my screeen but now dust blobs. Good luck, with convergence like yours, if its that way corner to corner, I would look at a dust blob fix before returning it.