I know more about Canon F-1 focusing screens than I do about Nikon F2 screens. You might try testing two screens to see if you get a different reading. Canon made a line of L screens (lasermatte) for the F-1 and F-1n cameras. When I use them I do not make any exposure adjustments. I suggest that you pose this question in the Nikon forum on photo.net. The reason I like an E screen rather than a B screen is that the grid lines of the E screen are a good sharpness reference. I have two FE bodies and one FE2. I did not have a problem loading the FE with an MD-12 attached. I have one MD-11 and one MD-12.