I'm from one EU country, live in another, I know that the delta between the two is always 2 hours.
Because EU and US switch DST at different times, in the multi-national software companies I worked there is this two week period when the delta changes, and there are mails and mis-scheduled things all around.
It's not a huge thing, but what is the benefit of each country randomly switching times, just for the sake of sovereignty. Next people will advocate using true solar time and getting rid of full hour based deltas.