You can't rely on the tyre checkers sadly, there are so many different wheel size options/tyre size options between years etc. Ideally you should look at the tyres on the car, and order the same (assuming they were the same from the factory). For example
https://www.wheel-size.com/size/ford/focus/ so many different options!
And don't worry about the EU rating, they're not worth thinking about.
But the 205s do sound the correct/common size for the 16" from the factory. I believe the US market commonly use the 215/55/16 whereas the EU market use the 205/55/16, might be that?
But the 215s wouldn't have caused any major issues, although might not be best having different sizes front to back.