Questioning myself and the world about Berlin’s new opening hours, I received a newsletter this evening that answered my question. At least to a certain extend.

Berlin-Mitte.com has a search engine which gets you businesses and their new opening hours. To check out what’s going on in Mitte and more important when, follow this link:
http://www.friedrichstrasse.de/cms/cms/tablestruktur.php?komfort=oeff&&site=2