I think they're not physically relocating the servers, but just rearranging them on the title screen based on population/traffic stats instead of just grouping them by location - there's no information to suggest otherwise.

Also at the moment the servers are only located at Square Enix HQ in Japan, and Montreal Canada (I believe it's hosted at Eidos, given the fact in the end credits 'IT engineers' at Eidos Montreal are credited, but don't quote me on that) - there are no servers in Europe or England at this time. Servers listed as 'EU' are actually the same as the 'NA' ones, as they're hosted in the same place (Montreal).