Sounds a lot like another gimmick to me. Unfortunately there is no industrystandard for calculating ballistic coeficient. Comanies can and DO manipulate BC to their advantage.
BC is only one of many, many factors that effect point of impact. The oneI think would come into play here the most is barrel harmonics. Since you're talking about using different weight bullets, you'll have to use different powders and charges,and will get different burn rates. This means the bullets will take differing amounts of time to leave the bore. Ifbullet Xleaves the bore on the down side of the "harmonics", and bullet Y leaves on the upside, you get different POI, no matter how close the BC. Make sense?