>>When I use the Alt+N, then try to save, the values in the grid are not recognised as being stored in the entity list. So there is something strange going on here as the values are fine if I tab out of the amount column.
>
>What happens if you change the UpdateSourceTrigger as I suggested:

<DataGridTextColumn Header="Amount" Width="*" Binding="{Binding cwd_amount, Mode=default, UpdateSourceTrigger=PropertyChanged}"
>                                                    CellStyle="{StaticResource AlignRight}"
>                                                    HeaderStyle="{StaticResource AlignRightHeader}"/>

Thanks, that has helped, sorry I missed it in your first message, I had meant to ask you to clarify.

The total is now updating properly, however the Charge Type is not being set properly. I've got some more digging to do here. :(

Later:
Setting the same updatesourcetrigger on the combobox column seems to work too!