It may be that your Western Europe is classified differently. You need to look at the individual Ethnicity maps and how they overlap each other. I have a large amount of Eastern European and have noticed that some cousins from that line are labeled Russian/Finland. Both of those ethnicity's overlap a large area of that part of the world. So the area is the same just different names. Whatever you inherited from your father, mixed with your mother, may tilt your result to a different name of the region based on the reference group that its compared against.

When determining Ethnicity, there is nothing on your DNA that says "I came from here". Instead, they take reference groups from different areas of the world and compare your DNA to theirs to see what group you are most like.

hopefully someone will come along and give you a more technical answer or point out somewhere where you can read more about this :)