Thanks for that. So I guess this leaves only the lighting not being correct. As for distance, I have 14mm to 500mm but up to 200mm I sometimes shoot from not too far away (especially for 85m 1.2) so I guess I can make a compromise and test shoot from a little closer than 25X. But even so when I use the 85 the lighting is even less than my living room's so maybe the lighting is of no issue (it is incandescent type by the way so at least it is the correct type)....I felt it would be too much trouble to get the targets printed at various sizes, hanged 100% vertically and use proper lighting (which I do not have).
Just to point out…if you test at a distance that's a fixed multiple of focal length (I use 25x and 50x), the target is always the same relative size. Personally, I just use an inkjet print of the target on letter-sized heavy matte paper for all my testing. Also, it does not need to be hung perfectly vertical, as long as you have a ballhead it's easy to align the camera to the target at a slight angle, and the software guides you through that.