I know it's not really the answer, but if you find yourself out of warranty and the price of an optical block means it's uneconomical, then try this: Set the masking to 2.5% in the menu (can't remember which off hand) and remember it is set for each resolution, then over zoom your lens to line up the sides of the picture with your screen. It might solve the issue for the sake of a bit of underscan. Note that you don't lose 1:1 pixel mapping doing this, just 2.5% of the sides of the image.
"Don't believe everything you read on the internet". William Shakespeare 1615