In fact, look at the WIC of the dog you posted

At 4 generations the WIC of the dog you posted is ZERO.
At 10 generations, it is only 7.
And yet he is still essentially 50% linebred Chinaman, top and bottom, via inbreedings on two completely different aspects of the same family.

By contrast each parent is 25-28% inbred at 4 generations, and 36-45% inbred at 10 generations, each inbred on different, specific individual Chinaman dogs.
This means you can take 2 inbred Chinaman dogs and "outcross" them to each other, because they're inbred on different individuals

This is a fabulous example of exactly what I meant by saying a person can "outcross within his own family" and essentially keep his dogs "Purebred X" forever