Although TFX is more than qualified to speak for himself, he's essentially saying that it's not the % of "Dog X" that's in the pedigree that counts as much as an experienced breeder keeping the key traits alive in the dogs.
In other words, if a 50% Abbot dog is just like Abbott, while a 75% Abbot dog is thin-boned and not quite the same, the experienced breeder will keep the 50% Abbott dog and pass on Abbott's traits ... while a paper-junkie will keep the 75% Abbott dog and only pass on "his name on a piece of paper" ...
Jack