We have new DNA updates that break down which parent our ethnic mixes come from. Fun. With us, there are not only the two of us but our Romanian sons and our nephew/son whose mother was 50% Jewish (now pretty clearly Russian Jewish according to the 1950 Census.) So even though my wife and I are descended from the coasts of That Giant Lake That Is The North Sea (plus some Irishmen), we gradually added in variety. And JA adding in a wife from the Philippines makes us now outrageously varied, The numbers are clearly wrong in some spots, but perhaps a bit closer than the last updating. Whether they will be able to trace another step back and differentiate my grandparents is unknown to me at present. Yet how can the numbers be that wrong? I have a 100% Swedish grandmother. That's 25% for me. So how do I get a number of 36%? Sure the East Anglians or the Scots might have brought in a little bit, but that's a big spread. If you are looking at your own numbers and scratching your head, I have a little knowledge.
1. This isn't your whole genome. This is a sampling of targeted spots which have had good value in identifying regions of origin in the past. It's likely to get better, and as whole genomes drop even lower in price - I think they are on the way to a hundred buck apiece at this point - the focus of these companies will increasingly be on interpreting this more complete data, not on finding good SNPs that can suss out whether the rumor your great grandfather was from West Yorkshire might be true or not.
2. There often isn't a lot of difference between nearby places that we think of as very separate, or necessarily a lot of similarity among places we think of as related. If ancestors were from "France" we think of them as likely to be the same, Normandy to Nice, and different from "England." But looking over 1000-3000 years ago, that is going to be deeply untrue. Where the boundaries now are and what languages people speak have interesting connections to the realities of the year 1, but thinking in those terms misleads more than enlightens. As an example, my wife's mother had both parents born in the Netherlands and was conceived there herself. (Family Story) But my wife's deeper DNA has consistently shown nothing from that area as a central focus. This new computation that identifies her mother's DNA more distinctly also shows none of it. However, it shows all the areas around it: England, Germanic Europe, some Scandinavians and some Balts. Does this mean that her ancestors were "really" from Germany or East Anglia, not Holland? That would be odd, because we have tracings on both sides back 400 years, all Holland. Somebody in that crew has got to be the result of persistence in the area. More likely, the identifying genes for East Anglia are also fairly common in Holland and Denmark and Saxony. Ancestry.com might call it an English identifier because it is more common there. But there was plenty of it in Holland also. On the coasts, people moved about and bred with a wider choice of folks. Up in the hills people stayed in their own valleys much more.
3. You don't actually inherit 50% from each parent. That's only the average. Most people fall between 45-55%, but there are some down to 40% and even down to 35% vs 65% is not unheard of. So you really might have gotten a different mix from your parents than your sister did. Maybe that helps you breath a sigh of relief.
I am also on Living DNA and one can see on both sites the same combos. Sweden is in the batch with the top half of Denmark, those are separate from Norway, which includes Iceland. Danelaw England shares a secondary circle with Normandy and Benelux. Western Lowland Scotland bleeds down into Northern Ireland (genetically true long before the Enclosure Act), Eastern Scotland into the continent and Scandinavia and the north of England, and The Highlands are a touch distinctive right the way back.
For those with any European Jewish ancestry, the belief has always been that there is a Generic Ashkenazi, with Galician and Litwak concentrations sprinkled in. A Chinese researcher looking at one of the million-sample experiments detected that there are in fact only two - the Litvak (think Lithuania) is quite distinct, but the Galician (think Transylvania/Hungary/Slovakia) DNA turns out to be indistinguishable from "all the rest." It's now Litvak vs All Others.