Try looking again at 10-generations
I would first look at ANY pedigree 10+ generations-deep,
minimum, before discussing what the coefficient is
Then I would answer you a 42+% inbred dog is highly-inbred, as the article states.
And you got it.
Your mistake was looking at a
4-generation pedigree to discuss "depth" ...
Typically, a WIC search spans
10-15 generations in order to have any meaning
Jack