That is way high. The old roof has to come off, some lathing to level it for the new roofing. New roofing material should come in (tops) at at three thousand and delivery charges. That should include the fasteners (screws) you'll need. Your 9-12 thousand sounds more like it. But then, I ain't a roofer. Definitely check around, and also spend the time to check other jobs the contractor has done and speak with the people he/she did the job for.