Is FEMA overpaying for roofing?

FEMA is paying contractors an average of $2480 to nail down blue tarps on damanged roofs. It's a two-hour job, and FEMA is providing the tarps for free. A company in Austin says they'd do the job for just $300: "Fixing roofs on Gulf Coast proves costly for taxpayers".
The contractors point out that they have to provide food and housing for their workers and thus have a very large overhead.
Let's assume that one crew can do three jobs in one day, and they have 10 people per crew. That would make the overhead $600 per person per day. What do you think?
UPDATE: Some of these workers are illegal aliens, making that a double-slap in the face.