They probably just have different blends of city/highway/speeds. Just like how gasoline cars have different estimates from different testing agencies, electric

They probably just have different blends of city/highway/speeds. Just like how gasoline cars have different estimates from different testing agencies, electric cars do too because they all have different efficiency curves. The ratings generally try to mimic the driving conditions of the region and automakers tend to optimize for their home turf. So it's not too surprising the American automaker does better on the American test and the Europeans do better on the European test.