A long time ago I worked for a company that had a "cost plus" contract to build and operate a thing. I took a management class while I was there and one of the people in the class was a consultant who had been hired to map the division's revenue flow. Almost everyone there was a manager and all of them were on the edge of their seats while he explained.

Basically, you mark up the little stuff that everything is built on ($1/page for copies, for example) so the margins look smaller when you get to anything substantial. So 3.3% is a meaningless number until it has been audited all the way down to the smallest purchases.