Yeah, you'll probably find many oldies in the DDR probably can't speak as good English as many of the young ones today as still in many people today they resent having to learn & speak English just to get by in business of their own country! I suppose it was less relevent then in the mid-life of the DDR.
It's also a difficult issue, I strongly object to the fact that many English speakers from whatever countries are very lazy and some don't even learn the basic language of wherever they go. But on the other hand, English is learnt from a young age in the majority of Western countries, so it is not uncommon to see people from a non-English speaking country speaking to natives of another non-English speaking country in English when abroad, as in many cases it is a common language.
Of course, it's always hard for the British & Americans to return the favour of speaking in a different language in non-specialist facilities due to the huge number of languages people could be speaking!