Difference of opinions between doctors

My wife and I have been trying IVF during some time, with 3 failed transfers. We live in Canada but we're from South America. We did the first 2 transfers in Canada (with my wife eggs) and the last one in our home country (with egg donor). After this last transfer, the doctor detected Protein S deficiency on my wife. He said this was the main reason of the pregnancies not advancing. In the meantime, we consulted a new doctor in Canada. She said Protein S is not that important, and she wants to do DNA tests on the embryos that we have frozen, and run other tests on my wife. The doctor in South America says there's no need to run DNA tests on the embryos because the egg donor is young and they did a good follow-up on her.

We were surprised to find this big difference in opinions, we were expecting the doctor in Canada to react to the Protein S finding, but she didn't care much about it.

Has anyone had this kind of experience with different doctors? It seems to me that doctors in Canada are conservative and don't like to take risks, but at the same time they want to try transfers over and over, which is a big toll for women.

Now there's also the factor that our embryos are frozen in South America, and bringing them to Canada seems quite expensive. So, I would be inclined to continue the process there.