When looking at the optics they definitely don't look like they co-witness perfectly with each other, which may very well be the case. However when looking through both optics they appear to line up well enough to use correctly, no noticeable misalignment. Larue does make a shorter version of the mount that I am using, the LT755-S, which is probably better suited to the XPS suite of EOTechs like I am using, as well as the 551, 552, etc. For EOTechs with a built in riser, 553, EXPS, etc. then the LT755 which I am using will probably co-witness perfectly with them.