Well, from what I've read in various posts, Anonymous, ETHNICITY isn't all that reliable. What is more reliable, if not 100%, is Y-DNA for tracing from father to father backward in time (women can't do this, they don't have a Y-DNA) and the fact that it ignores the maternal lines; or the mtDNA (for tracing the mother to mother backward in time which some people don't like because they want paternal lines not maternal lines (and men can do this track, they don't have any mtDNA); so then you have the autosomal, which is both parents' DNA tracked back into time, although some don't like this route because it's more limited to something like 5 or 6 generations and loses something after that
IN THE OLD days, there was the blood groups, A, B, AB, and O and these were mapped according to prevalence in regions of the earth. So ethnicity was an Idea tied to that.
Then there's the pitfalls about what pool of samples the company tested against. You can get a "false positve" for "ethnicity".
It is frequently a case of confusion, and many PM who test, will have that test done by 3 or more different companies. Which is something you might want to consider doing. And you might want to consider the autosomal test (for yourself) with each of these companies.