Strange or not Matthew, actually the Part 23 cost to certify is currently as we speak twice that much!!! Greg Bowles, GAMA Director of Engineering and Manufacturing says it's $50-100 million.
http://www.avweb.com/podcast/podcast...?kw=AVwebAudio
As you may or may not know a review of Part 23 is underway with many reforms including costs being considered. The objective with costs is to reduce them by at least half. My figure was based on this possible outcome so I applied some simple mathematical optimism for near future certification approval.
http://www.flyingmag.com/pilots-plac...23-time-change
From NBAA website, October 10, 2012:
"Speaking in the city that manufactures more than 40 percent of all standard general aviation (GA) aircraft in the world, Huerta said he expects the FAR Part 23 changes to slice new-aircraft approval cost by as much as half by ‘harmonizing’ the FAA’s rules with those of other countries. He cited a required wing-strength test, saying that each country might have a slightly different requirement for the test, costing manufacturers millions of dollars to make slight changes to satisfy each country"
The Primary Category cost is based on osmosis -talking and listening to people discussing the subject.
Your question about the Champ is exactly what the Part 23 review is all about which is basically to shift the Rules from the being weight based to being performance based.