My memory about it is that the dipswitch on a PE+ is not used, the software does not look at the dipswitch, except maybe for the one switch that sets 50hz/60hz input power. Don't know why they left the dipswitch on the board, unless it was only for that input power freq selection. But that doesn't explain what you are seeing with the 2 boards so I'm not sure.
On the PE (non-plus model) I think the dipswitch was used for various settings like you mention.
Someone more familiar with the PE/PE+ models will probably say for sure.