I've read enough to know that one cant even Identify which maintenance manual applies to his airplane. We know its a Piper PA32, that doesn't tell us the variant or serial number. As you can see by the graph I posted, there is a huge array of balancing data for the PA28 series, the PA32 series isn't the same way?
He mentioned someone would be contacting Piper, which is about the smartest thing he can do. They should be able to help physically identify and verify the parts on the plane are the correct ones.
For all we know the trim tab was repaired at one time and its causing the problem, or the wrong balance arm is installed, or maybe the factory screwed up its not the right stabiliator, or more likely, the manual is wrong.