it might be related to a change in when PDFCreator reads the settings from the registry.
It should work, if you make sure PDFCreator is completely closed in between, as I think the registry settings are only read on startup (I will need to ask our developers to be sure).
Perhaps the "skip print dialog" option will help; this skips the print dialog, showing only the save dialog where the filename and location can be set.
Or you could use the COM interface to change the settings on the fly.
You can change printers profile as described here: