The BEV seems to be saying that in Vienna daylight-saving was observed for only 10 days in 1945, allegedly.
Um, remember that there was a war on, and somewhere around then Vienna changed hands. Is it possible it moved from Berlin time to Allied time?
The word "allegedly" is from the BEV's document which says (in German, I've used Babelfish to translate to English): In the year 1945 the summer time without special regulation was waived by the end of the war. This procedure was given usually by the invasion of the occupation troops and took place thus in individual regions at different times, so e.g. in Vienna allegedly on 12 April 1945. Exact documents over it are not well-known us. The odd thing about it is that the Red Army captured Vienna on April 13, and (if the BEV is to believed) immediately canceled DST and therefore switched the clocks to be 1 hour ahead of UTC. And yet, when the same Red Army took Berlin, our other information is that it switched Berlin's clocks to use Moscow Summer Time (UTC+4) or to Central European Midsummer Time (UTC+3), depending on whether you talk to Joerg Schilling or to the PTB. At this point it may be impossible to tell what really happened with the clocks back in that chaotic time, when people had far more important things to worry about than time zones and DST.