It would be interesting to do a wider test like this but instead of trying to clump people together into "American English" and "British English" it would be interesting if the data point was "in which city do people speak like you do?" and create a geographic map of accents.

I'm from the south of Sweden and I've had my "accent" made fun of by people from Malmö just because I grew up outside of Helsingborg, because the accent changes that much in just 60 kilometers.