If you are confident this is the problem then prove it to them on paper. Figure the loss due to ACTUAL footages, passives, etc. Compare your figures to the design. I was on a sweep project in Arizona a few years ago and we quickly discovered the design EOL levels were incorrect more than 50 % of the time. Sometimes the levels were inverted, but more often than not they were just wrong. We had to a)fix the problem or b)document the design problem and write up a PDR. Once we figured out what was going on, we saved ourselves a lot of hours in the field chasing down "phantom" problems.
This is CABL.com posting #319497. Tiny Link: cabl.co/mbvhl