@Kovid: Thanks for replying and confirming that it is not Calibre that is doing something wrong as Sony suggests.
About flabbergasted I enclose another screenshot from the PRS-T2. The problem is also discussed at the Sony forums (
http://community.sony.nl/t5/eReading...T2/td-p/359582). This problem is repaired by a firmware update after half a year of complaining and the Dutch consumers authority (Consumentenbond) contacting Sony. At that time I did not have Calibre yet (great software, thanks).
@Alex: Thanks for letting me know I didn't miss an option.
@Zetmolm: I did inform Sony - with screenshots - that the same pages look good in Calibre and bad in Digital Editions but Sony claims that they cannot reproduce.