I have spend some frustating hours trying to figure out, why my number format did not work properly in my preview mode. Data was brought in the dashboard by BIWS connection.
I thought it had to do with the locale, as the numebrs where formated with a comma as decimal token (as is custom here). And thus formatted Xcelsius must interpreted as Text.
Even adding the parameter &locale=en_US to the wsdl did not work. In the end I gave up and just multiplied every value with 1 (I never connect directly to my data output, always by reference).
Just now, my colleauge found out it was due to another missing parameter.
After adding &ConvertAnyType=true to my wsdl, my numbers where recognised as numbers and not as Text anymore. (Be careful: do not format your number in the WebI report otherwise it still will not display correct )