I would make sure the scale is accurate before I did any more adjusting. An inaccurate scale would be my first suspect if two bows showed the same lack of draw weight problem.
I too have problems with cable rubbing my cams on my guardian. Its due to excessive cam lean. I have sent it back once and they replaced my limbs. Still didn't fix it.
I had that problem on an 07 Allegiance. I replaced the cams and fixed it. I took the strings and cables off of the bow and mounted my laser on the bow. I aimed it at the cam and rotated it and could see the problem was with the cam and, of course, it was even worse when stressed by the cables and string. You may want to look at replacing the cams.