Yes, it's all about the money trail, you are correct.
No, I do not test birds. I am confident in my flocks, though, as we know, things can change on a dime since no one can see an invading germ. That is another reason testing is only good for the actual bird tested and on the actual day of testing-disease can happen at any time in between tests.
The NPIP folks who bought birds from me have never had one of mine test positive after leaving here. No symptomatic birds. Other than genetic/hormone based stuff from substandard hatchery stock like internal laying, for the most part, and arthritic joints from very old hens (7-11 years old, and we have quite a large number of those),we have had few issues with health. No contagious respiratory illness here ever. And my best friend in KY had a renowned vet who cared for her Arabian mare as well as her chickens, so he knew my birds, having handled many of them, as she had gotten quite a few from me here in GA at one time or another years ago. I've consulted him on several occasions long-distance. And I had a long, very informative conversation with the former state vet in GA a few years back about one of my birds that told me a lot of stuff that facts would probably not believe, but he was awesome (no, the one I called him about was not contagious). The current state vet here, I would not trust to test for a hangnail. The most recent NPIP customer, a repeat customer over the years, told me he completely trusted the health of my birds, but the main thing is he trusts me, personally. I would never sell any questionable birds to anyone, ever.
I'm not sure you mean by "full" NPIP. There is the basic stuff, but do you mean testing for MG/MS and other diseases? There is no official designation for different levels of NPIP that I'm aware of here in the U.S. One line of my heritage Barred Rocks came from hatching eggs sent to me by one of the NPIP testers for the state of GA, but not before he tested his new breeding rooster for every disease known to man, above and beyond the basic NPIP. Maybe that's what is meant by "full" NPIP?