Aimpoint 9000 vs Aimpoint ACO

Has anyone compared these 2 scopes? I have 9000 I'm trying now but was wondering how similar ACO is to it?
Jon

ACO?? Is that the Carbine Optic? I'm thinking of getting  one
 I can check if the AMU has tested it. I do have the 9000 on my Match Gun 2. Have no problems and being it's top end is Aluminum the weight is not a problem either. I have talked to Adam as at this time no reason or what may be causing the problem and if it is the 9000 but zero seems to change for no reason from match to match on different AMU shooters guns.
 Mounting and screw tension seems to be the same. This past year at Perry it happened to Adam. First shot slow fire in 45 match was a 6, thinking it was his error he shot again 6!!!! Made the necessary adjustment and it shot good the rest of the match! Yet nothing was changed from the previous days Center Fire match. Other AMU shooters have experienced the same thing from time to time.