In a perfect market, they would be able to sell their services at the same price as the value of those services. So if they build a system for the Veterans Administration (VA) that saves $1 million, they should get $1 million for it. Their EOY revenue would reflect their value created.
But they are actually selling to themselves. They are a part of the federal government, and their customers are other agencies. So the price they should charge is actually (value created - effort to get paid).
If they waste $500,000 of man-hours to get that $1m, then the government loses $500k for no reason, other than for 18F to be able to point to $1m in revenue as proof of services provided.
The government as a whole also loses out if price is an issue for the buyer, but a net win for the whole organization. If bureaucracy means that a department isn't willing to spend $1m to reap $2m in savings, because maybe the benefits are nebulous or internal politics or any of the other crazy things that people do in big organizations, then it actually benefits the government as a whole for 18F to do it for free.
While I like that they focus on revenue to prove the impact they are having, selling products to other agencies shouldn't be profit maximizing. Any inefficiencies, either to the buyer or seller, are taxing to the organization.
Side note: $32m is nothing. I'll take that any day over people building GIF hosting and SnapChat.