Okay, first off, I own three collimators and I once checked the same scope set-up, with all three of which, none agreed, completely. I pretty much expect the elevation to be off but sure would like the windage to be in. .....
Don't know if it will make a difference, in your case but I once encountered what you have described. This scope was a variable and I had the magnification, set too high. Turned it down to min, in order to see the matrix. Wish I could remember more details. .....
My first pass on bolt-action rifles, is removing the bolt, anchoring the rifle and looking through the bore and onto my target that I have set-up, 18Yds. away. I have a small back yard. ....
Be Safe !!!