The website is here, then click on the Test Updates tab.

I think the difference is that some of SpaceShipOne's flights were captive carry missions, some were glide tests, and others were powered missions. Looking at their test updates page, here are the flights they've posted so far in chronological order:

Flight 01: 20 May 03 - captive carry flight
Flight 02: 29 Jul 03 - captive carry flight
Flight 03: 07 Aug 03 - 1st glide test
Flight 04: 27 Aug 03 - aborted glide test
Flight 05: 27 Aug 03 - 2nd Glide test
Flight 06: 23 Sep 03 - 3rd Glide test
Flight 07: 17 Oct 03 - 4th Glide test
Flight 08: 14 Nov 03 - 5th Glide test
Flight 09: 19 Nov 03 - 6th Glide test
Flight 10: 04 Dec 03 - 7th Glide test
Flight 11: 17 Dec 03 - 1st Powered flight
Flight 12: 11 Mar 04 - 8th Glide test
Flight 13: ?? ??? ?? - 2nd Powered flight

They have not yet posted the most recent test. I look forward to the writeup. So, SpaceShipOne has now flown 13 times, but has only been released 11 times.