Yes, when generating forms, the modeler assumes your attribute names are in CamelCase. So CamelCase is converted to 'Camel case', BTWCode is converted to 'B t w code', and BtwCode would be converted to 'Btw code'.
Of course, nothing prevents you to change the name afterwards, its just a generated heuristic name. The modeler has no built in support for special abbreviations introduced by the Dutch law.