I would question the accuracy of breed determination especially with breeds having open or appendix herdbooks.
Also, DNA is only as accurate and the database. I have a dog that I had to submitt DNA 3 times I kept getting letters telling me the sample was a bad sample. I know that the samples were done correctly and sent to the lab in the correct manner. The problem comes from the fact that one company started the DNA process and Database for what ever reason a different company now processs DNA. Instead of collecting new DNA on dogs previously processed (expensive) the new company said it could adjust the DNA markers as the first companies markers and the current ones markers are not exactly the same. The problem is the sire of my dog was DNA'd early on with first company. They will not admit that the real problem was the DNA database. However, when I submitted the 3rd sample I called and we had a conversation. It was a little heated on both sides. In the conversation, I requested to be informed of the problem with the sample rather than a form letter listing 7 or 8 possible problems. In addition, that this was my 3rd and final submission and I would be thru with that registry. Amazingly the DNA sample went thru and parents verified. The results read the the results were adjusted.